Where simply the author’s name and date of publication are given in a note, full details of that title are to be found in the Bibliography (see p.472).
1 Lawton, 1990. This publication is a historical summary of British grouse research since 1956.
2 Sangster et al., 2004. ‘Willow Ptarmigan (Red Grouse)’, and ‘The correct scientific name of the Red Grouse is Lagopus l. scotica’ and ‘of the Rock Ptarmigan is Lagopus muta’. We ignore such renaming.
1 Although some northern breeding populations avoid deep snow by wintering hundreds of kilometres south of their breeding range, and many populations move shorter distances between summer and winter habitats.
2 Ground-dwelling species (e.g. red grouse, ptarmigan) have feathered toes, whereas arboreal species (e.g. hazel grouse, black grouse, capercaillie) have small scales or ‘pectinations’, whose primary function is probably to grip branches (Drovetski, 1992).
3 Their basal metabolic rate is higher than that of a generalised non-passerine bird of the same body weight (Andreev, 1988b, 1991).
4 Meleagrininae.
5 Simplified from Drovetski (2003). Other work agrees largely with this family tree but gives different estimates of the time when grouse diverged from turkeys (6 million years ago according to Drovetski, and 20 million years ago according to Pereira & Baker, 2006). This is because the ‘molecular clock’ used to estimate timescale is debatable. The Miocene lasted from about 23 million to about 5 million years ago, and so both estimates agree that grouse diverged from turkeys during that epoch. Like the Pliocene and Pleistocene, the late Miocene was a period of global cooling, and so the statement that grouse evolved during such a climatic period stands, irrespective of the timescale.
6 Drovetski, 2003.
7 The Pliocene and Pleistocene.
8 Together, the Nearctic and the Palaearctic comprise the Holarctic, which is more or less the northern hemisphere north of the Tropic of Cancer.
9 Until recently, 18 species were generally recognised, but the blue grouse has just reverted to two separate species, the dusky and the sooty grouse. Some authors argue that the red grouse should be restored as a species from its present status as a subspecies of willow ptarmigan, and that the southwestern and northeastern subspecies of spruce grouse should be restored to species (Gutiérrez et al., 2000; Lucchini et al., 2001; Dimcheff et al., 2002; Schroeder, 2006).
10 The ‘ptarmigan’ group includes the red grouse. Molecular evidence is causing some authors to revert to the old split between Tetrao (the two capercaillie) and Lyrurus (the two black grouse), a convention we use in this chapter.
11 Drovetski, 2003.
12 See Chapter 6.
13 Harrison, 1987.
14 The exception proves the rule. In the Cantabrian mountains of northern Spain, there are few native conifers and capercaillie winter in forests of beech, oak or holly.
15 Although some populations of ruffed grouse, like capercaillie, seem able to survive without conifers.
16 Storch, 2000a.
17 Such as birch, alder, rowan, beech, aspen, hazel and willow.
18 Zwickel, 1992.
19 See Chapters 5 and 6.
20 The Caucasian black grouse, the Chinese grouse and the Siberian grouse are probably ‘vulnerable’ according to IUCN criteria, and the Gunnison sage grouse is considered ‘endangered’ (Storch, 2000a). The lesser prairie-chicken is being considered for federal listing as ‘threatened’ or ‘endangered’.
21 See Chapter 14.
1 Brown, 1993.
2 www.anglo-norman.net/articles/missinglink. xml, accessed 5 September 2006; Rothwell, 1991.
3 MacGillivray, 1837, 1855. He named all Lagopus as ptarmigans, Britain having brown ptarmigan or red grouse or red ptarmigan, and grey ptarmigan or common ptarmigan.
4 Hantzsch, 1914; Soper, 1928; Macpherson & McLaren, 1959; Wilson, 1976; Cramp & Simmons, 1980; Höhn, 1980; Johnsgard, 1983; Hagemeijer & Blair, 1997; Lindström et al., 1998. Several names are onomatopoeic (Holder & Montgomerie, 1993a). Chinese names for willow and rock ptarmigan include niao, like a hen’s nasal contact call, whereas Inuit names resemble male calls, e.g. akigikvik for willow ptarmigan in Baffin Island and nakatogak for rock ptarmigan in east Greenland. Capercaillie in Russian is glukhar, with stress on khar and sounding guttural like part of the bird’s song, and Sámi has tsuukhts (Semenov-Tyan-Shanskiy, 1960), sounding like the last swishing part of the song.
5 Cym–ithas Edward Llwyd (1994). Cym–ithas Edward Llwyd, a natural history society that works in Welsh, has attempted to standardise common names of animals, with the approval of museums and the Countryside Commission for Wales. The list has the plural of red grouse as grugieir cochion, ptarmigan plural as grugieir gwynion, blackgame plural as grugieir duon, and capercaillie singular as grugiar coed and capercaillie plural as grugieir coed.
6 Grant, 1941; Grant & Murison, 1956, 1965, 1974.
7 Muir is Scots and moor English, both pronounced ‘moor’, although muir is increasingly heard as ‘myoor’, following its spelling. Variants are the Aberdeenshire ‘meer’, west Angus ‘mair’, and central ‘mair’ or ‘mor’, with the middle vowel sound pronounced like the Danish.
8 MacGillivray, 1837; Longmuir, 1867; SND.
9 Gordon, 1915.
10 Spoken with an extra vowel to ease pronunciation, as ‘taramachan’, and meaning ‘a ringing sound’, like the cock’s call. The accent indicates a long vowel, but in his dialect surveys James Grant (pers. comm. 2006) always heard it short. The derivative torman is often used in Gaelic poetry for the sound of streams running down hillsides (James Grant, pers. comm. 2006), with the onomatopoeic pronunciation ‘toroman’. In Ross-shire, tormachan an t-sléibhe was used for ptarmigan, which adds to the likelihood that tormachan derived from tormachan. To conclude, the evidence indicates that tormachan means ‘grumbler’ or ‘croaker’ (Dwelly, 1971; Lockwood, 1976; Ó Dónaill, 1977; MacLennan, 1979; MacBain, 1982; Brown, 1993).
11 For example, heathfowl in a list that includes muirfowl (Rose, 1785).
12 MacEachainn, 1971.
13 Ó Dónaill, 1977.
14 Pennie, 1951.
15 James Grant (pers. comm. 2006) considers this the likely explanation of the transmutation, since ‘1’ often becomes ‘r’, e.g. bruadal becomes bruadar.
16 Robertson, 1898.
17 Robinson, 1985.
18 Hjorth, 1970.
1 Salomonsen, 1939.
2 Höhn, 1980.
3 Gutiérrez et al., 2000.
4 Chapman, 1924.
5 Steen, 1989.
6 Cramp & Simmons, 1980.
7 Kloster, 1928.
8 Potapov, 1985.
9 Explanation of deep, undrifted snow powder categories: (1) scarce, due to frequent wind (or many days with snow-free ground), e.g. east Greenland, Taimyr, Kazakhstan, Komander Islands, Svalbard (Glen Esk, Amchitka, Hitra); (2) uncommon, due to fairly frequent wind and open landscape (or calm conditions but very shallow snowfall), e.g. Cairngorms Alpine land, Avalon, Iceland, Seward, southwest Alaskan coast, Kodiak, Anadyr, Koryak, Finnmark (Yakutia); (3) common, despite more wind than in 4, because of heavy snowfalls or shelter from mountains and woodland or scrub, e.g. Senja, Lierne, Finnish Lapland, Leningradskaia, Altai, middle Yukon River, northwest British Columbia, west Newfoundland; (4) widespread, due to deep snowfall and fairly calm, cold air, e.g. central Alaska, upper Yukon River, interior Yukon Territory, central Urals, Switzerland, Siberia.
10 References on body-weight, snow and climate for Fig. 12. Lagopus lagopus: Kristoffersen, 1933; Ulianin, 1939; Myrberget et al., 1969; West et al., 1970; Pulliainen, 1976; Andreev, 1982; Thomas, 1982; Myrberget, 1984b; Mossop, 1988; Watson, unpublished, at Glen Esk. Rock ptarmigan: Lid, 1927; Grammeltvedt & Steen, 1978; Thomas & Popko, 1981; Mortensen et al., 1983, 1985; Steen & Unander, 1985; Watson, 1987b; Emison & White, 1988; Ó. Nielsen, unpublished, at Hrisey; Brenot et al., 2005, the birds were very light (mean 417g) in the continental climate of the French Alps, and 449g in the more oceanic Pyrenees, but these were autumn weights, and so are not used in the graph. Both species: Semenov-Tyan-Shanskiy, 1960; Moss, 1974; Cramp & Simmons, 1980; Potapov, 1985, and references therein; R. Potapov, pers. comm. 2007. Snow and climate: Pruitt, 1960; Borisov, 1965; McKay et al., 1970, and references therein; Fullard, 1976; many ecological references in Chapters 2 and 3.
11 Henderson, 1977; Moss & Watson, 1987.
12 Jenkins et al., 1963.
13 Lance, 1975.
14 Potapov, 1985.
15 At Glenamoy there is virtually no winter in meteorological terms, i.e. days with a mean temperature below freezing.
16 Yurlov, 1960; Lance, 1975; Voronin, 1978.
17 Dementiev & Gladkov, 1952.
18 Potapov, 1985.
19 Myrberget, 1975, Fig. 1; Watson & Moss, unpublished.
20 Body-weight rose quite fast at Avalon (Bergerud et al., 1963), north Norway (Myrberget, 1975) and Churchill (Hannon et al., 1998), and yet slower at Kerloch. Winter comes later at the first three than on Russian tundra, and later still at Kerloch. Hudson (1986a) reported quite fast growth in north England, but did not name locations or altitudes, so climate cannot be assessed.
21 Myrberget, 1975.
22 Bent, 1932.
23 Moss, 1972a.
24 Bent, 1932.
25 Moss, 1972a; Steen et al., 1992.
26 Watson, unpublished.
27 Classification by resemblances and differences, often synonymous with taxonomy.
28 Hanson, 1935; Salomonsen, 1936, 1939.
29 Lorenz, 1904; Potapov, 1985.
30 Watson & Moss, unpublished; Steen, 1989.
31 A juvenile cock shot in 1967 on Meall Odhar had much white on its body and wings, but its size and reddish feathers seemed like a red grouse (Watson, 1967c). Also on Meall Odhar a dead juvenile found in August 1990 showed the same features (AW, unpublished). A hybrid shot on Kinveachy estate in 2005, one of a brood of three (Frank Law, pers. comm.), was identified as such from DNA evidence (Stuart Piertney, pers. comm.).
32 Parmelee et al., 1967.
33 During spring in Alaska, a hen rock ptarmigan solicited a cock willow ptarmigan that had a small patch of dark spring feathering on each side of his head. Evidently his dark patches resembled a male rock ptarmigan’s black moustache enough to stimulate her inappropriate behaviour (Moss, unpublished).
34 Potapov, 1985.
35 For example, in the Cumberland Peninsula.
36 Cramp & Simmons, 1980. The first tentative introduction was in 1870, but was not very successful (Michèle Loneux, pers. comm. 2005). Other releases during 1910-20 in east Belgium along the German border led to abundant birds, but they became scarce after 1950 as habitat loss proceeded. The last Belgian record was in April 1974, of a cock heard in the Hautes-Fagnes Nature Reserve, created in 1966 at 670m altitude along the German border (Ruwet, 1988). The cock was on Fagnes de la Baraque Michel, where blackgame still occur.
37 Witherby et al., 1944; Hudson, 1993.
38 An introduction in the 1890s failed (see Chapter 4). In the 1970s, Deeside birds were released on the islands. They nested, but cats killed some hens and the birds became extinct. Overgrazing by sheep had also reduced food and cover (Watson, unpublished).
39 Myrberget, 1976; Cramp & Simmons, 1980; Steen, 1989; Hagemeijer & Blair, 1997; Stone et al., 1997; Storch, 2000a, b.
40 Adam Smith, pers. comm. 2007, based on counts by the Game Conservancy Trust.
41 Hammond, 1979.
42 Hudson, 1993.
43 In O’Dwyer, 1995. Watson et al. (1995) estimated over 10,000 pairs, extrapolated from counts.
44 For example, Bent, 1932; Höhn, 1980; Steen, 1989.
45 For a definition of ‘heath’, see Chapter 11.
46 For example, Kastdalen et al., 2003.
47 Ratcliffe, 1990.
48 Watson & Miller, 1976.
49 Savory, 1986; Palmer & Bacon, 2001.
50 Parr, 1992.
51 Longstaff, 1932; Soper, 1940; Manning, 1948; Dementiev & Gladkov, 1952; Harper, 1953; Jenkins, 1953; Manning et al., 1956; Höhn, 1959; Macpherson & Manning, 1959; Semenov-Tyan-Shanskiy, 1960; Manning & Macpherson, 1961; Savile, 1961; Jenkins et al., 1963, 1967; Watson, 1963c, 1965a, b, 1979, unpublished; Savile & Oliver, 1964; Bergerud & Mercer, 1966; Parmelee et al., 1967; Soichiro et al., 1969; Williamson & Emison, 1969; Bergerud, 1970a; MacDonald, 1970; Géroudet, 1978; Watson & O’Hare, 1979a; Marcström & Höglund, 1980; Luder, 1981; Parker, 1981a, 1984; Alamany & de Juan Monzon, 1983; Fasel & Zbinden, 1983; Montgomerie et al., 1983; Ryzhanovskiy et al., 1983; Myrberget, 1984b; Pedersen, 1984; Potapov, 1985 and references therein; Unander & Steen, 1985; Hannon & Barry, 1986; Olpinski, 1986; Martin & Cooke, 1987; Boudarel, 1988; Brodsky, 1988a; Gardarsson, 1988; Mossop, 1988; Ryabitsev, 1989; Huber & Ingold, 1991; Cotter et al., 1992; Holder & Montgomerie, 1993b; Holder, 1994; Bossert, 1995 and references therein; Nielsen & Pétursson, 1995; Hannon et al., 1998; Watson et al., 1998, 2000; Cotter, 1999; Scherini et al., 2003; Smith et al., 2005; G. Scherini & G. Tosi, unpublished.
52 ‘Polar desert’ is shown by vegetation maps (Beschel, 1970; Alexandrova, 1970, 1988), and is characterised by low plant production (Alexandrova, 1970, 1988; Bliss et al., 1984) and low precipitation with cold summers (MacKay et al., 1970). Eurasian polar deserts have richer soils, more plant species and less bare ground than North American ones (Svoboda, 2002). The milder ‘Arctic desert’ (Kankaanpää, 2002) extends further south in Canada than in Eurasia. Vegetative cover and production are greater in Arctic Eurasian heath, and greater still on Scottish Alpine land and moorland (see Table 6). The greater vegetative cover and production in high-Arctic and Arctic Eurasia than in these zones in Canada explain the lower densities of willow and rock ptarmigan in Canada than in the equivalent zones in Eurasia.
53 Fewer sheep, along with little or no burning, have caused much coastal heathland to change to scrub and woodland.
54 Ulianin, 1939; Höhn, 1980. Photographs show loose, sandy soil, indicating dry weather conditions. There are no bogs, and birds in the southeast of the range breed in semi-desert (Roald Potapov, pers. comm. 2007).
55 Watson et al., 1966.
56 Bracts at the base of each flower in the floret spike.
57 Mikheev, 1948; Hannon et al., 1998.
58 Savory, 1977.
59 Dementiev & Gladkov, 1952.
60 Hannon et al., 1998.
61 Irving et al., 1967a.
62 Stokkan, 1992.
63 Kitshinskiy, 1975. Although on the New Siberian Islands, the most northerly land occupied by willow ptarmigan, birds deposit much fat in autumn.
64 Andreev, 1980.
65 Gabrielsen et al., 1977, 1985; Gabrielsen & Steen, 1979; Gabrielsen & Unander, 1987; Steen et al., 1988a; Ingold et al., 1992.
66 Slagsvold, 1975. Air temperature in June during the incubation period is related to the percentage of young in the subsequent shooting bag.
67 Hudson, 1986a.
68 Moss et al., 1990b.
69 Jørgensen & Blix, 1988. Ambient temperature is air temperature at bird level.
70 Aulie & Moen, 1975.
71 Boggs et al., 1977; Pedersen & Steen, 1979.
72 Aulie, 1976a, b.
73 Jørgensen & Blix, 1985.
74 Höglund, 1970; Erikstad, 1979, 1985b; Erikstad & Spids0, 1982; Erikstad & Andersen, 1983. Chick growth and survival were poorer in cold summers with few insects than in a warm summer with many insects (Erikstad, 1985b). Rain and cold reduced the feeding times of two- to five-day chicks by 60 per cent, and their crops held almost twice as much food in a warm, dry summer as in a wet, cold one. Chicks grew more slowly and survived worse in broods that moved more, presumably in search of food. In cold, wet summers, chicks aged zero to eight days in small broods grew faster than those in large broods. Chicks in large broods spent longer being brooded, with less time for eating.
75 Bent, 1932; Dementiev & Gladkov, 1952. The ‘orderly action of winter flocks led Eskimos and northern Indians to regard them as organized societies and, in their mythology, to designate them as ptarmigan “people”‘(Irving et al., 1967b).
76 Weeden & Ellison, 1968; Hannon et al., 1998.
77 Cramp & Simmons, 1980. Zimmerman et al. (2005) noted willow ptarmigan at sea in calm weather near the Alaskan coast on 30 August, when 125 flew over the sea and around a boat. A few ‘appeared to be exhausted after landing on the vessel, exhibiting rapid breathing with open beaks’, but panting also signifies birds being hot. At least ten landed on the water to rest. Other observations of birds flying at sea are given, including two bathing, and a rock ptarmigan sitting on the water.
78 A greater percentage moves at high than at low density.
79 Jenkins et al., 1963.
80 Watson et al. (1984b) called it ‘spring emigration’.
81 See Chapter 14.
82 Leslie, 1911.
83 Watson, 1966.
84 Andersen, 1986; Andersen et al., 1986. A variant is that Kazakh birds that have bred in woodland move to open steppe after the first snowfall, but return to winter in woodland (Ulianin, 1939).
85 Watson, 1966, unpublished.
86 For example, Jenkins et al., 1967; Hörnell-Willebrand, 2005.
87 A case of homing involved a cock that was radio-tagged in spring 1987 on Strathnairn, released 35km away, and then refound on Strathnairn a year later (Hudson et al., 1988).
88 Jenkins et al., 1963. Also, in a Grouse Migration Enquiry in 1932-9, Scottish keepers ringed young red grouse (1938, Field, p. 1289). Out of 56 birds recovered in their first shooting season, 52 were shot on their own moors, some ‘within 100yds. [90m] or 400yds. [370m] of the spot where they were ringed’, three went 1-2 miles (1.6-3.2km), and one 8 miles (13km). Out of 12 shot in later years, seven were on their own moors, four moved 1-2 miles (1.6-3.2km), and one 12 miles (19km). Four of the seven were in their second year and one each in their third, fifth and seventh years. Scandinavian willow ptarmigan after their first shooting season tend to move more (Cramp & Simmons, 1980, citing Olstad, 1953; Hörnell-Willebrand, 2005).
89 Jenkins et al., 1967.
90 Watson, 1965a; Watson et al., 1984b. A case occurred after we applied fertiliser to boost heather growth and protein content at Kerloch (Watson et al., 1984a). The area held an extremely high density of territorial grouse from autumn to spring 1971-2. Just before nesting, about 40 per cent of cocks and hens emigrated. The area would have provided good food for wintering and for hens to build reserves before nesting, but was so crowded that few chicks would be recruited. Hence, we suppose, birds went elsewhere to breed.
91 Watson et al., 1984b. In willow ptarmigan, too, two-thirds of territorial birds emigrated from Tranøy just before nesting, in 1971, a year of high density (Myrberget, 1984b, 1989a). Their age was not reported.
92 Some old willow ptarmigan at Chilkat Pass shift to different territories in a subsequent spring (Schieck & Hannon, 1989; Hannon & Martin, 1996), but willow ptarmigan there do not hold territories over winter like red grouse.
93 Lance, 1978a; Mountford et al., 1990; Watson et al., 1994; and Myrberget (1989a) in willow ptarmigan.
94 Watson et al., 1984a.
95 Watson & Miller, 1976.
96 Lovat, 1911; Moore et al., 1975.
97 Miller et al., 1970. Muirburn occurred annually for four years. Grouse density rose in the last year of burning and stayed high for two more years. To keep it high may require burning every few years.
98 Lance & Phillips, 1975.
99 Watson et al., 1987.
100 Watson, 1966, 1979; Picozzi, 1968; Moss, 1969; Watson & Hewson, 1973; Nethersole-Thompson & Watson, 1974; Moss et al., 1975.
101 Hudson, 1992.
102 Phillips & Watson, 1995.
103 Parry, 1978; Simmons, 2003.
104 This contrasts with soil damage caused by modern farming, but it involves deep ploughing in autumn or winter on enlarged fields (usually up and down slopes), compaction by machines, and autumn-sown crops with much bare ground. Prehistoric cultivation was carried out in summer, with hand tools used to work the surface soil.
105 Parry, 1978.
106 Lee et al., 1992.
107 John Lee, Des Thompson & Sarah Woodin, pers. comm. 2006.
108 Hudson (1992) used weather data to estimate heather production, because annual production on Kerloch was related positively to summer air temperature and negatively to rainfall (Miller, 1979).
109 Lindén & Pedersen, 1997.
110 Marcström & Höglund, 1980.
111 Bergerud, 1970a; Pedersen, 1984; Hannon & Barry, 1986. Densities at Avalon are 1.4 cocks per km2, at Anderson River 7.7 and at Dovrefjell 15.
112 Phillips et al., 1992a.
113 Mercer & McGrath, 1963; Bergerud & Mercer, 1966; Myrberget, 1988; Gardarsson, 1988. In 1962, the 19,000ha Brunette Island, 16km from mainland Newfoundland, had an estimated 37.9 cocks per km2, falling to 3 per km2 in 1965. This compared with 1.5 per km2, falling to 0.7 per km2, on the mainland in the same years. The 137ha Tranøy had an average density of 74 adult birds per km2, with a peak of 85 pairs per km2. There was no study area on the nearby big island Senja, but far lower densities there were obvious to Norwegian biologists and to AW who was with them. At Hrisey there was no study area on the nearby mainland, but lower densities there were obvious to Icelandic biologists and to those of us who were with them.
114 When a fenced plot prevents voles from moving in or out, they increase to a very high density (Krebs et al., 1969). Even though an island does not prevent grouse moving in or out, it may constrain movement more than on the mainland.
115 On a 16ha area in spring 1973 (upper) and 1972 (lower).
116 Watson (1979) gave densities on two areas combined. The table gives data in spring 1978 on the 14ha Cairnwell and the adjacent 13ha Meall Odhar Beag. No fires had burned since 1950. Keepers eliminated crows in most years and killed foxes. Shooting was by occasional ‘walking up’.
117 On 28 March 1954, an area over granite at 450—550m. The hen figure is from Watson, unpublished.
118 Unburned unshot upper moorland. Watson (1979) combined cocks and hens, and Watson (unpublished) has separate values. Ranges across years were 4.7-14.2 in cocks and 0-14.2 in hens.
119 Unburned unshot upper moorland. Statistical analyses (Watson et al., 2000) used the data of Watson (unpublished). The table shows ranges across years.
120 Means for 14 study areas in 1969 before experimental treatments began on some areas, density ranges being 0-4.9 for cocks and 0-3.7 for hens.
121 Counts in 1958 on 200ha of mostly grassy overgrazed moor near Kinlochbervie.
122 Watson & Moss, 1979; Bergerud & Gratson, 1988.
123 Haydon et al., 2002.
124 Watson et al., 2000.
125 Authors’ analysis, unpublished.
126 Moss & Watson, 2001.
127 Moss et al., 1996.
128 Lindstrom et al., 1995.
129 Siivonen, 1952.
130 Myrberget, 1984b, c, 1987a, 1988, 1989b; Steen et al., 1988b.
131 See, for example, the lemming study by Framstad et al., 1993.
132 Steen & Erikstad, 1996.
133 Moss & Watson, 2001. In this review there were seven examples from Lagopus lagopus and L. mutus combined.
134 Bergerud, 1970a; Hannon & Barry, 1986; Andreev, 1988a.
135 Mercer & McGrath, 1963; Weeden, 1963; Bergerud & Mercer, 1966; Jenkins et al., 1967; Watson, 1979; Watson et al., 1984b; Myrberget, 1984b. Semenov-Tyan-Shanskiy (1960) recorded August numbers from close to o and up to 20 per km2 in Laplandskiy, and 3-135 seen per 100 hours in September-December.
136 Moss et al., 2000a.
137 Hudson, 1992.
138 Watson et al., 1995.
139 Mackenzie, 1952.
140 O’Hare, 1973.
141 Barnes, 1987; Hudson, 1992.
142 Mackenzie, 1952.
143 Watson et al., 1989.
144 Siivonen, 1948, 1952; Semenov-Tyan-Shanskiy, 1960.
145 Moss & Watson, 2001.
146 Phillips & Watson, 1995.
147 Straker-Smith & Phillips, 1994; Phillips & Watson, 1995.
148 Estimates of survival from radio-tagged birds are more accurate, but are usually imprecise owing to small samples. Also, radios may affect survival. Studies in red grouse and willow ptarmigan found no impact of radios on survival, but their statistical power to detect such an effect was low. A few studies in other species suggest an impact, e.g. predators at Windy Lake killed a higher percentage of radio-tagged male rock ptarmigan (Cotter, 1991). The type of harness may affect survival, but in Cotter’s case it made no difference whether he used necklaces or back harnesses.
149 Bergerud, 1970a, 1988; Johnsgard, 1983; Bergerud & Mossop, 1984. Apparent ‘survival’ from one spring to the next can be calculated by dividing the number of ‘old adults’ (in their second or later springs) on an area in the current spring by the number of old plus ‘young adults’ (in their first spring) present in the previous spring. This and similar methods, however, take no account of movement. The method that confounds adult survival with that of newly reared youngsters uses the number present in spring divided by the total number (adults and young) present in the previous autumn.
150 They used radios to follow birds from spring to autumn, and rings to find return rates after winter. Raptors killed many birds, including cocks establishing territories, hens before laying and during incubation and in the early brood period, and both sexes in the late-brood and moult periods. Autumn hunters shot 1.4-3.0 times more cocks than hens.
151 Moss & Watson, 2001.
152 Hudson, 1986a.
153 Watson & Miller, 1976; Watson, unpublished.
154 Myrberget, 1976; Hannon et al., 1998.
155 Weeden, 1963; Bergerud, 1970a; Myrberget, 1984b; Hannon et al., 1998, 2003. For example, 1.2 cocks per hen at Chilkat Pass, Avalon and Churchill.
156 Jenkins et al., 1963, 1967; Watson et al., 1984b. In addition, on Yamal, 30 per cent of territorial cocks were unmated after a fourfold increase in density over four years (Ryabitsev, 1989).
157 Watson & Jenkins, 1968.
158 Hannon, 1983. Several cock willow ptarmigan had three hens each and one had four.
159 Manniche, 1910; Soper, 1928; Bent, 1932; Mikheev, 1939, 1948; Salomonsen, 1939, 1950; Dunaeva & Kucheruk, 1941; Macpherson & Manning, 1959; Semenov-Tyan-Shanskiy, 1960; Jenkins et al., 1963; Watson, 1965a; MacDonald, 1970; Cramp & Simmons, 1980; Johnsgard, 1983; Montgomerie et al., 1983; Potapov, 1985; Steen & Unander, 1985; Potapov & Flint, 1987; Holder & Montgomerie, 1993a; Hannon et al., 1998; Cotter, 1999.
160 Sharp & Moss, 1981.
161 Jenkins et al. (1963, 1967) recorded differences in average hatch dates. They drew no conclusion about weather, but hatching came early after mild springs in 1957 and 1961, and late after the cold snowy springs of 1958 and 1962. Laying dates of willow ptarmigan at Churchill are correlated with dates of snow melt (Martin & Wiebe, 2004).
162 Myrberget, 1987b; Hannon et al., 1998.
163 Moss et al., 1981. The median is the midpoint when observations are arranged in order of size, commonly used where there is a skew, as is usual with laying dates. The order in which individual hens began laying was related to that in the next year. This also applied to their clutch size, weights of eggs and newly hatched chicks, and chick survival.
164 For example, Dunaeva & Kucheruk, 1941; Jenkins et al., 1963; Bergerud, 1970a. At Kolyma, a low percentage of young in late summer was attributed to ‘unmated or non-breeding’ birds (Andreev, 1988a). In Scotland, low percentages of young usually result from deaths of downy chicks. This is easily overlooked unless visits are made almost daily.
165 Watson & Moss, unpublished. One at Glen Esk in 1959, when many hens died, and one at Rickarton.
166 Jenkins et al., 1963; Campbell et al., 2002.
167 Bent, 1932.
168 Watson, 1977b.
169 Watson & Jenkins, 1964.
170 Semenov-Tyan-Shanskiy, 1960.
171 Dementiev & Gladkov, 1952.
172 Gordon, 1925.
173 Höglund, 1970; Watson, unpublished.
174 In red grouse (Jenkins et al., 1963; Watson & Moss, unpublished) and willow ptarmigan (Westerskov, 1956; Bergerud, 1970a), although the incubation period is 19 days on Timansk (Dementiev & Gladkov, 1952) and 18 days in Kazakhstan (Ulianin, 1939).
175 Semenov-Tyan-Shanskiy, 1960; Pulliainen, 1978; Erikstad & Spidsø, 1982; Lance, 1983.
176 Dementiev & Gladkov, 1952.
177 Jenkins et al., 1963, 1967; Watson & O’Hare, 1979a.
178 Myrberget, 1985; Munkebye et al., 2003.
179 Steen & Parker, 1981.
180 Moss & Watson, 1982.
181 Sandercock, 1993.
182 Mercer, 1968; Hannon et al., 1998.
183 The possibility that clutch size has increased with time cannot be ruled out, because data at Glen Esk were from 1957-61, at Kerloch from 1962-5, at Rickarton from the 1980s, and at Strathmore and Speyside from the 1990s.
184 Jenkins et al., 1963; Bergerud, 1970a; Erikstad et al., 1985; Myrberget, 1986a.
185 Myrberget, 1986b.
186 Voronin, 1991.
187 Moss et al., 1981.
188 Myrberget, 1987b.
189 Myrberget, 1986b.
190 Kirby & Smith, 2005.
191 Martin, 1984.
192 Parker, 1981a, 1984, 1985.
193 Martin & Hannon, 1987. In early autumn, young willow ptarmigan from renest broods were poorer at eating and at processing coarse winter food of twigs than earlier young (Stokkan & Steen, 1980).
194 Jenkins et al., 1963.
195 Jenkins et al. (1967) recorded a mean of 13 per cent of nests robbed (the range in different years was 6-30 per cent) for red grouse at Kerloch, and Myrberget (1988) recorded 28 per cent of nests robbed (a range of 9-86 per cent in different years) for willow ptarmigan at Tranøy. In British grouse, the proportion of eggs that hatch (excluding robbed and deserted nests) tends to be high, e.g. averaging 90 per cent or more in red grouse and Scottish ptarmigan. It can vary between years, e.g. at Glen Esk from 70 per cent in a poor year to 95 per cent in a good year when hens laid big clutches (Jenkins et al., 1963). None the less, this was of little import for breeding success, compared with chick losses (Watson, 1971).
196 Brittas, 1988. He studied breeding indirectly by noting the percentage of young shot in autumn.
197 Watson & O’Hare, 1980. Glenamoy bogland held an average density per km2 of five grouse in spring and about 100 blackface ewes. In terms of biomass per km2, this comes to 3kg of grouse and 4,500kg of sheep, not including the lower density but far larger size of Aberdeen Angus cattle.
198 Phillips, 1994, 1999. A 350ha area at Priestlaw held low spring numbers in nine years, varying from nine pairs to 36 cocks and 39 hens, but they bred well (in different years, 4-10 young were reared per hen). Birds at Misty Law bred almost as well (3.6-9.6 young per hen) over 14 years, but in the five years before a full-time keeper was appointed they averaged only 0.7-2.1 young per hen. Raptors were protected at Misty Law throughout.
199 Jenkins et al., 1963; Marcström & Höglund, 1980; Steen et al., 1988b.
200 Parker, 1984.
201 Bevanger (1995) estimated that the 95,000km of high-voltage electricity wires in Norway kill 50,000 willow ptarmigan annually.
202 Hannon et al., 1998. On Bolshezemelskaya, unusually heavy losses of adults and especially first-year birds occurred in 1971-5, when lemmings were scarce and predators turned to willow ptarmigan (R. N. Voronin, 1976, Ékologiya 5, 95-8, cited by Cramp & Simmons, 1980).
1 Mitchell, 1906. The anonymous Scottish account was from 1721-44, probably the early 1720s.
2 Pennie, 1957; Watson, 1965b, c, 1972; Höhn, 1980; Steen, 1989; and photographs therein.
3 Cramp & Simmons, 1980.
4 Moss, 1974; Elison, 1980; Emison & White 1988.
5 Gordon, 1915.
6 MacDonald, 1970.
7 Moss, 1974.
8 Potapov, 1985, pers. comm. 2005. Russian birds are smallest in the subalpine belt of Tarbagatay, Altay, Sayan, Hahgay and Transbaikal.
9 Elison, 1980; Emison & White, 1988. Holder & Montgomerie (1993a) reported large birds in ‘extreme northern and Aleutian’ islands of North America. Both regions have windy winters.
10 Potapov, 1985. On Svalbard they winter several degrees of latitude north of the northernmost mainland wintering grounds on Taimyr at 75°N.
11 Semenov-Tyan-Shanskiy, 1960; Weeden, 1979; Pulliainen, 1980.
12 Salomonsen, 1939. Some hens in northeast Greenland have as much black on the head as cocks.
13 Gordon, 1951; Savile, 1951.
14 Steen & Unander, 1985.
15 Watson, 1987b.
16 Brockie, 1993.
17 Gordon, 1915.
18 Jacobsen et al., 1983.
19 MacDonald, 1970; Braun & Rogers, 1971.
20 Vaurie, 1985; Browning, 1979. On Svalbard, golden-brown summer feathers camouflage birds against the brownish background (Steen & Unander, 1985). This might be worth studying elsewhere.
21 See Brockie’s (1993) painting of a Greenland cock, which in terms of colour is almost like a red grouse.
22 Holder et al., 1999.
23 Miltschew & Georgiewa, 1998.
24 Pfeffer, 1997.
25 Potapov et al., 2003; Potapov, 2004.
26 Salomonsen, 1950.
27 Pearson, 1907; Salomonsen, 1939; Potapov, 1985; Storch, 2000a.
28 Cramp & Simmons (1980) were too definite about the species. They were citing Williamson (1970), but his original detailed account makes it clear that it was not certain which species still occurred in the 1960s.
29 Watson, unpublished. High densities of sheep on the Faeroes have reduced the extent of Alpine heath plants such as blaeberry and heather, and their heavy grazing has lowered the height of the vegetation, thus removing physical cover.
30 MacPherson, 1893; Holloway, 1996.
31 Baxter & Rintoul, 1953.
32 Gordon, 1915.
33 Thom, 1986; Holloway, 1996. However, two were seen in the Southern Uplands in 1992 and one in 1994 (annual Scottish Bird Report).
34 Gordon (1944) reported an introduction there, but after a few years none was seen.
35 Witherby et al., 1944.
36 Watson, 1965b.
37 Ibid.
38 Thom, 1986.
39 Annual Scottish Bird Report.
40 Watson, 1965b; Gibbons et al., 1993; Kaye, 2007; and distribution maps therein.
41 Cook, 1992; Watson, unpublished.
42 Harvie-Brown & Buckley, 1895.
43 Buckland et al., 1990.
44 Wynne-Edwards, 1954.
45 Cramp & Simmons, 1980.
46 Holder & Montgomerie, 1993a.
47 Storch, 2000a.
48 Ratcliffe, 1990; McGowan et al., 2003.
49 Watson, 1965b. On 260km2 of Alpine land.
50 Rae, 1994.
51 Braun & Rogers, 1971.
52 Watson, 1965a.
53 Ibid; Foggo, 1980; Rae, 1994.
54 McVean & Ratcliffe, 1962.
55 Study areas in order of decreasing latitude: Ny-Ålesund on Svalbard (Unander & Steen, 1985); Clavering Island in Greenland (Gelting, 1937); Lyngen and Lofoten in Norway (Watson, 1957a, unpublished); Baffin Island (Watson, 1957b, unpublished); north Iceland (Gardarsson & Bossert, 1997); Eagle Creek (800m) in Alaska (Weeden, 1965b, 1972); the five Scottish areas of Sgribhis Bheinn (180m, whose climate is ‘very exposed with extremely mild winters’ (Birse & Robertson, 1970)), Foinaven (370m), Applecross (550m), Cairngorms (610m) and Lochnagar (670m) (Watson, 1961, 1963a, 1965b); Amchitka in the Aleutian Islands (Jacobsen et al., 1983); the Kurile Islands (loom; Potapov, 1985); Altay (1,300m) in China (Yue-Hua, 1995); Aletschgebiet (1,980m) in the Swiss Alps (Bossert, 1995); Lombardy (2,300m) in the Italian Alps (Scherini et al., 2003); Haute-Savoie (1,800m) in the French Alps (Desmet, 1988a); the French west Pyrenees (2,260m; Boudarel, 1988); the Spanish east Pyrenees (1,900m; Novoa & Gonzales, 1988); and Honshu in Japan (Soichiro et al., 1969).
These are lowest limits. The average is often higher, e.g. in Scotland, where it is 240m on Sgribhis Bheinn, 760m on the Cairngorms and 820m on Lochnagar (Watson, 1965b). Other data on altitudes are in Semenov-Tyan-Shanskiy (1960) and Potapov (1985).
56 Watson, 1963b.
57 Watson, 1965a, unpublished. In the warm summers of the Pyrenees and French Alps, birds favour cool aspects ranging from north by east to southeast (Boudarel, 1988; Desmet, 1988b).
58 Potapov & Flint, 1987.
59 Soper, 1928; Holder & Montgomerie, 1993a.
60 Soper, 1940; Olpinski, 1986.
61 Gardarsson & Bossert, 1997.
62 Gardarsson, 1988.
63 Bent, 1932; Soichiro et al., 1969; Williamson & Emison, 1969; Bossert et al., 1983; Jacobsen et al., 1983; Marti & Bossert, 1985; Boudarel, 1988; Desmet, 1988b; Novoa & Gonzales, 1988; Scherini et al., 2003; Favaron et al., 2006. Photographs in the Aleutians show nests hidden in tall vegetation, and others were ‘well hidden in the long grass’. Photographs of Amchitka show the main vegetation as crowberry-lichen heath, like a moor. Nearly all nests on the Japanese area were at the border of pine scrub, one at the edge of juniper scrub, and one underneath alder branches. In the Swiss Alps, photographs in summer show a hen resting under a scrubby tree, and a hen on a nest partly concealed under woody branches, with surrounding dense plants above her. Wintering birds in the Pyrenees use rhododendron shrub-land. Hens and chicks in the French Alps favour vegetation taller than 20cm, with scrubby coniferous trees and bushes of rhododendron and juniper, and most Lombardy hens have nests that are completely concealed under rhododendron and juniper. Pennie (1957) noted that since the rock ptarmigan is the only gallinaceous bird in Iceland and south Greenland, it is found in summer in situations ‘which would appear more appropriate for a Willow Grouse’. Icelandic nests in thick cover ‘are not uncommon’ and the bird ‘occupies the niche filled in Britain by the Red Grouse’.
64 Moss, 1974.
65 Watson, 1965a.
66 Gelting, 1937; Salomonsen, 1939; Cramp & Simmons, 1980; Bernard-Laurent, 1987; Andreev, 1975.
67 Moss, 1968.
68 Watson, 1964.
69 Gelting, 1937; Gardarsson & Moss, 1970.
70 Elison, 1980; Emison & White, 1988.
71 Gelting, 1937.
72 Moss & Watson, 1984.
73 Gelting, 1937; Gardarsson & Moss, 1970.
74 Watson, unpublished.
75 Veghte & Herreid, 1965; Johnson, 1968; Braun et al., 1993; Martin et al., 1993.
76 Moss, unpublished.
77 Chapman, 1924; Mortensen et al., 1983, 1985; Stokkan & Blix, 1986; Stokkan et al., 1986. Chapman reported very fat birds in autumn, weighing 1kg each. Recent studies show that they feed continually in the dark winter months, so the weight of crop contents varies little. Captive birds that are fed pellets ad lib undergo the same seasonal changes in weight, fat deposition and depletion, and sometimes fast for several days even when food is available. In contrast, Norwegian rock ptarmigan have negligible body fat and are not adapted to withstand prolonged starvation.
78 Stokkan, 1992.
79 Gabrielsen & Unander, 1987. See also Chapter 3. The temperature of the eggs is a fairly steady 32°C before the incubating hen’s feeding trip, drops 5-60 during the trip, but rises rapidly to 32°C after she returns. It takes 30-60 minutes before her heart rate and breathing rate fall to resting levels. Her rates rise each time she turns her eggs, when the eggs’ cool sides touch her incubation patch.
Huber-Eicher (1995) studied Swiss nests at 2,000m. When hens returned after feeding, the eggs’ temperature had very seldom fallen below 25°C and never below 22°C. Eggs can tolerate low ambient temperatures. Although low egg temperatures may not harm embryos, they lengthen the incubation period. Hens were off their nests a total of 40-90 minutes per day.
80 Anvik, 1969; Theberge & West, 1973; Pedersen & Steen, 1979.
81 Marti & Bossert, 1985.
82 Gardarsson, 1988.
83 Watson & Rae, 1993.
84 For example, Salomonsen, 1950. Birds are not in northeast Greenland during the three darkest months (Manniche, 1910). Hundreds have been seen crossing Hudson Strait between Baffin Island and Labrador, and often ‘alight on ships and are easily caught’ (Bent, 1932).
85 Soper, 1928.
86 Freuchen & Salomonsen, 1960. ‘Multitudes of Ptarmigan then are crowded in winter quarters in the southernmost parts of the Arctic. In March the main migration toward the breeding places in the north takes place. The first flocks consist almost entirely of males; later in March new flocks leave the wintering area, and these include many females. The percentage of females in the migrating flocks gradually increases, until in April they predominate. Sometimes in early March, when the landscape everywhere still has a winter-like aspect, the first flocks of Ptarmigan arrive; they may include hundreds if not thousands of birds. During the following days the number increases until they appear everywhere in vast numbers. Preferably, they settle in areas that the wind has swept clear of snow. Tens of thousands are shot or snared by the Eskimos in these March days, though in normal years when the Ptarmigan usually is scarce and local in the north, they are not particularly interested in catching this minor game. The Ptarmigan during such invasions are extremely fearless and even settle among the houses. They usually appear to be very thin and emaciated. Apart from the myriads killed by the inhabitants, a large number perish during migration or after arrival at the place of destination, and as a rule the density of birds on the breeding places after such mass movements is not essentially larger than in normal years. In April the migration appears to end, although it may sometimes continue into May. These Ptarmigan migrations, which are known in Baffin Island, Labrador, Greenland, Siberia and other areas, take place with tolerable regularity every tenth year. Particularly large numbers were encountered in 1889-1890, 1928-1930 and 1949-1950. Between these peak years there are periods in which Ptarmigan are very rare. Such a year was 1954 in Greenland, when you could walk for days without catching a glimpse of any Ptarmigan or find any sign of them. The difference between the situation in such years and that in peak years when Ptarmigan crowd everywhere is striking.’
87 Hantzsch, 1929.
88 Watson, 1957b.
89 Storch, 2000a.
90 Salomonsen, 1950.
91 Gudmundsson, 1972; Gardarsson & Bossert, 1997.
92 Preble, 1908; Bent, 1932.
93 Hannon et al., 1998.
94 Gudmundsson, 1960; Weeden, 1964.
95 Cotter et al., 1992; Cotter, 1999.
96 Bossert, 1980.
97 Unander & Steen, 1985; Olpinski, 1986; Holder & Montgomerie, 1993b.
98 Gudmundsson, 1960; Gardarsson & Bossert, 1997.
99 Gelting, 1937. ‘In the old Eskimo settlements one is almost always certain to meet ptarmigan mothers with their broods…On July 4 the first female ptarmigan appeared with her young. Subsequently, several broods arrived, and until August 3 they were observed every day.’
100 Polunin, 1948. At Canadian Inuit settlements in the 1930s, Nicholas Polunin found bright green vegetation, including plant species that favour ground enriched by excrement.
101 Gardarsson & Bossert, 1997.
102 Gardarsson, 1988. They were found up to 900m near Akureyri in July 1949 (Watson, unpublished).
103 Gordon, 1915.
104 Watson, 1963b.
105 Millais, 1909. In September 1907, ‘Two days of ordinary snow made no impression on these hardy birds, but a blizzard from the north on the third day made all the Ptarmigan, to the number of, I should say, 800 to 1000, leave the tops and north faces and come flying in coveys to a sheltered corner. They kept arriving for about two hours in a continuous stream. Next morning I passed through this sheltered hollow, and moved thousands of Ptarmigan, which only flew for a short distance.’
106 Boudarel, 1988. They winter at 1,980-2,260m, and summer at 2,260-2,540m.
107 Watson, unpublished.
108 Gardarsson, 1988.
109 Watson, 1965a, b, unpublished. He suggested that much Arctic heath may be a poor source of food. Chemical analyses show that one of the main species, Arctic heather (Cassiope tetragona), is low in nutritional quality (Gelting, 1937).
110 Watson et al., 1998.
111 Cycles are interesting because they are evidence of unstable, as opposed to the more usual stable, population dynamics.
112 Nielsen & Pétursson, 1995; Zbinden & Salvioni, 1997; Cattadori & Hudson, 1999, 2000; Cattadori et al., 2000.
113 Weeden, 1965a, b; Weeden & Theberge, 1972; Cotter, 1991.
114 Watson et al., 1998.
115 Moss & Watson, 2001.
116 Watson, 1965a; Unander & Steen, 1985.
117 See Chapter 3. It is assumed that once an adult settles in summer, it will not be outside that area next summer. This is problematic where breeding ranges vary with snow-lie, as in Alaska. Even in the Cairngorms, some basins have no birds in snowy summers (Watson, 1965a).
118 Most studies are done in a short season during the summer, so ‘summer’ is short and winter comprises most of the year. Hence a 10 per cent summer loss (3-4 per cent per month), and a 40 per cent winter loss (about 5 per cent per month) differ little when expressed per month.
119 Weeden, 1965a; Watson et al., 1998. ‘Summer’ in the study at Eagle Creek ran from late May to early August, and on the Scottish areas from late April to early August.
120 Cotter et al., 1992.
121 Gardarsson, 1988.
122 Nielsen, 2003. Also, 27 per cent of radio-tagged cock ptarmigan were lost in May-June, all to gyrfalcons, but none in July-August.
123 Much of this difference would be down to the fact that ‘winter’ comprises most of the year in these studies, as explained in note 116.
124 Olpinski, 1986; Holder & Montgomerie, 1993a.
125 Parmelee & MacDonald, 1960; MacDonald, 1970; Holder & Montgomerie, 1993a, b. Three hens nested in a cock’s territory on Bathurst Island, but he had been injected with testosterone.
126 Watson, 1965a; Watson et al., 1998. At Cairnwell and Meall Odhar this went the other way, with more cocks per hen during years of population increase. Unmated cocks there survived on very small territories in marginal habitat during years of high numbers towards and at the peak.
127 Watson, 1965a.
128 Weeden, 1963, 1965a; Soichiro et al., 1969; Unander & Steen, 1985; Desmet, 1988a; Cotter et al. 1992; Cotter, 1999; Scherini et al., 2003. Bossert (1995) recorded on average 1.4 territorial cocks per hen during years of population increase, and 2.9 during declines.
129 Gardarsson, 1988.
130 Olpinski, 1986.
131 Brodsky & Montgomerie, 1987; Holder & Montgomerie, 1993a. They did not state the numbers of unmated cocks.
132 Gardarsson, 1988.
133 Cotter et al., 1992.
134 Also, Gardarsson (1988) stated that Hrisey’s predator situation was atypical because the island lacked Arctic foxes, which killed many ptarmigan on the mainland and ‘may prey selectively on incubating and brooding hens’. The proportion of cocks among shot adults was 47 per cent on the mainland, but on Hrisey it was significantly lower at 41 per cent. The poorer survival of summering cocks was ‘accounted for solely by the somewhat unusual predator situation on Hrisey’.
135 For example, Holder & Montgomerie, 1993b.
136 Emison & White, 1988.
137 Elison, 1980.
138 Watson & Parr, 1973; Watson et al., 1998.
139 Marti & Bossert, 1985.
140 Steen & Unander, 1985; Rae, 1994.
141 Watson, 1963b. Gordon (1932) also found a Scottish nest in tall heather.
142 Watson, unpublished.
143 Watson (1972) gave 1.5 per day, but this was a printer’s error for 1.5 days per egg, as implied in later sentences.
144 Steen & Unander, 1985; Rae, 1994.
145 Watson, 1965a; Watson et al., 1998.
146 Watson, 1965a; Steen & Unander, 1985; Watson et al., 1998.
147 Watson, unpublished.
148 Moss & Watson, 1984.
149 Gardarsson & Moss, 1970; Watson, 1972, p. 20; Gardarsson, 1988.
150 Steen & Unander, 1985; Rae, 1994.
151 Bailey, 1993.
152 Marquiss et al., 1989.
153 Watson, 1965a; Gardarsson, 1988; Cotter et al., 1992; Holder & Montgomerie, 1993a; Watson et al., 1998.
154 Watson, 1996a; Watson & Moss, 2004.
155 Watson & Shaw, 1991.
1 For fuller details of the bird and its behaviour, see Cramp & Simmons (1980) and Lindström et al. (1998).
2 As in both sexes of all four species.
3 The verb ‘lek’ has also come to mean the display itself, and the place where the display is done (i.e. the display ground or arena).
4 Hovi et al., 1995.
5 Kokko et al., 1999.
6 Rintamäki et al., 1995.
7 Höglund et al., 1995.
8 Rintamäki et al., 1995.
9 Hovi et al., 1994; Alatolo et al., 1992.
10 Hovi et al., 1996.
11 Höglund et al., 1999.
12 Regnaut, 2004; Regnaut et al., 2006.
13 Höglund et al., 2002.
14 Alatolo et al., 1996. This applies to any one morning at a lek. Unless the hen re-lays, it probably also applies to each spring as a whole, but this is difficult to establish unequivocally.
15 Rintamäki et al., 1998.
16 Bowker & Bowker, 2003.
17 Zeitler, 2000.
18 We use Lyrurus in Chapter 1, where it is useful for distinguishing between the Lyrurus and Tetrao lineages.
19 In: Kirkman & Hutchinson, 1924.
20 Storch, 2000a.
21 Hancock et al., 1999. Of the displaying cocks, about 5,000 were in Scotland, 1,700 in northern England and 150 in Wales.
22 www.rspb.org.uk/scotland/action/ blackgrouse.asp (as at 3 September 2006).
23 Tucker & Heath, 1994.
24 Whether the killing of predators (foxes and crows may legally be killed) is necessary to the long-term success of such management is a contentious issue.
25 Rhododendron ferrugineum.
26 Klaus, 1991. Increased temperatures, increased levels of carbon dioxide and input of atmospheric nitrogen seem also to have contributed to faster tree growth and more closed canopies. Furthermore, nitrogen pollution itself enriches soils and encourages grassy vegetation at the expense of dwarf shrubs.
27 Starling-Westerberg, 2001; Baines et al., 1996.
28 Lindley & Mellenchip (2005) provide some useful guidance from their experience in Wales.
29 ww.gct.org.uk/blackgrouse/decline.html (as at 23 December 2003).
30 Thom, 1986. Baines et al. (2000) illustrated a typical sequence of events with counts from four Sitka spruce or lodgepole pine plantations in Perthshire. Counts were done with pointer dogs in August, one, four, six, eight, ten, 12 and 14 years after planting. Here, the density of greyhens in late summer increased from an average of about three per km2 at one year after planting to some ten at four years after planting. It then fell back rapidly to six per km2 at six years after planting and further declined to about one per km2 by 12 years after planting. Cock densities followed a similar course but peaked at only four per km2.
It is not clear how much of this increase was due to immigrants attracted from surrounding moorland or to young birds reared within plantations. Breeding success in the four plantations remained at about two chicks per hen throughout, and so breeding success did not decrease as hen densities declined with canopy closure.
It was also not clear whether breeding success in plantations differed from that on unplanted moorland, because there were no comparable counts from before planting or from surrounding moorland. The decline in density was apparently due to a decline in the area of open ground with dwarf shrubs, not to waning breeding success. The authors illustrated the likely role of open ground by contrasting two plantations. In one with less than 10 per cent open space, hen densities peaked at about four hens per km2 some six years after planting, whereas in a plantation with more than 30 per cent open space they peaked at about 11 hens per km2 at 13 years after planting and were still at four hens per km2 16 years after planting.
31 Pearce-Higgins et al., 2007.
32 Scarifying allows trees to root more deeply while leaving ground vegetation largely undisturbed. It also drains the ground more freely, especially on soils with iron pans, which are broken by the tine.
33 Geoff Shaw, pers. comm. 2004.
34 Grass is ‘grazed’, while woody plants such as heather are ‘browsed’. This difference becomes clumsy when animals eat both grassy and woody vegetation, and so we often use ‘grazing’ to mean ‘grazing or browsing’.
35 Baines, 1996.
36 Calladine et al., 2002.
37 The 128km2 reserve includes about 20km2 of semi-natural Scots pinewood and about 13km2 of trees of planted origin, plus moorland and Arctic-Alpine ground up to the summit of Cairn Gorm.
38 Not all the open ground was suitable for woodland grouse, but the deer that were counted on open ground were likely to use the woodland and so affect the habitat of woodland grouse.
39 There was some canopy closure and loss of dwarf shrubs in planted parts of the pinewood, especially in the north, but this does not affect the argument.
40 This was practical conservation management and not a scientific experiment. Consequently it was not replicated and there were no comparable data from reference sites where sheep or deer were not reduced. Fences were removed in the early 1990s, and crows and foxes were killed in some years (1992-6 and 2001 onwards) but not in others, as part of a trial in predator management. These issues complicate the interpretation, but for present purposes we can regard capercaillie numbers as a control for factors such as predator abundance and deaths from flying into fences, which are likely to have affected the two woodland grouse species in similar ways.
41 Capercaillie lek counts (not shown) followed much the same course as numbers of capercaillie seen during deer counts, i.e. there was no boom and bust.
For analyses of population dynamics, counts of blackcocks at leks are a more useful measure of population trends than numbers seen during deer counts. This is because lek counts are of known precision, as they are based on two counts in the same season, and here we use the average count. Also, blackcocks at all leks in the reserve were counted, and so the number reflects the total breeding population of cocks in the reserve. Furthermore, blackcocks are more likely to be locally recruited than greyhens (see below), and hence any associations between local conditions and numbers are easier to interpret.
42 This ratio includes hens with no chicks.
43 Data from RSPB staff, and from Anneke Stolte, who collated them.
44 The 45 quadrats were laid out on a grid covering the pinewood, with measurements in 1989, 1992, 1997 and 2003.
45 Some figures express densities or breeding success in natural logarithms, because this shows trends more clearly. Below is a chart for converting this logarithmic measure of breeding success to the number of chicks per hen:
46 Population change was logeNt – log Nt-1 where Nt was the number of displaying cocks in year t, breeding success was loge(chicks per hen in year t-1, plus one). Vegetation growth rate was as in Table 15, except that in 1992 it was estimated as (1.81 + 3.13)/2 = 2.47 and in 1997 as (3.13 +1.26)/2 =2.20. Simple correlations: between population change and breeding success r = 0.66, P = 0.19; between population change and vegetation growth rate r = 0.86, P = 0.0003. Partial correlations: r = 0.40, P = 0.23 and r = 0.78, P = 0.004, respectively.
47 Juvenile heather shoots (no flowers) contain more protein and phosphorus, and are more digestible, than mature (flowering) shoots. The greater nutritive value of juvenile heather shoots is thought to contribute to the well-documented increases in the density of red grouse that follow muirburn.
48 Cramp & Simmons, 1980.
49 In the north Pennines, Warren & Baines (2002) found that natal dispersal by eight radio-tagged first-year hens ranged from 5km to 19km, with an average of 9km. In the French Alps, Caizergues & Ellison (2002) radio-tagged 39 young black grouse. Most (81 per cent) young greyhens left the 836ha study area to nest 5-29km from their site of capture.
50 Autocorrelations are correlations between numbers in year t and numbers in year t-n, where n is the lag, here 1-6 years. A significant positive value (one above the 95% confidence limit) means that high (low) numbers in year t went along with high (low) numbers in year t-n. The sudden decline in size of the Buccleuch autocorrelation coefficient at six years suggests a six-year ‘moving average’ process.
51 www.gct.org.uk/research/blackgrouse/ index.html (as at 22 December 2003).
52 Baines, 1991.
53 Hughes et al., 1998.
54 Moss, unpublished data.
55 In 1985-93 the mean number of chicks per hen at Glen Tanar was 1.3 (standard error 0.3).
56 A comparison of annual variations in breeding success with weather records from Glen Tanar in 1975-2003, as done for capercaillie (Moss et al., 2001), revealed no obvious relationship.
57 The legend in question is ‘The Brave Little Tailor’, a fairy tale collected by the brothers Grimm.
58 Baines et al., 1996.
59 Picozzi et al., 1999.
60 In 1982-9, for example, the number of chicks reared per hen in the old pinewood of Glen Tanar was 1.8 (standard error 0.4) and on moorland edge at Birse some 6km away it was 1.1 (standard error 0.2), not significantly different (Moss & N. Picozzi, unpublished data).
61 Willebrand, 1992; Caizergues & Ellison, 1998a.
62 Caizergues & Ellison, 1998b.
63 A ‘closed’ population is one with no movement in or out.
64 Picozzi, 1986.
65 Warren & Baines, 2002.
66 Calladine et al., 2000.
1 Suter et al., 2002; Pakkala et al., 2003. This should not be taken to mean that capercaillie maintained by artificial means, such as killing predators, indicate a healthy forest.
2 Capercaillie were blamed, amongst other things, for biting off the leading shoots of growing Sitka spruce and leaving them lying on the ground – but these shoots are so tender that strong winds often blow them off Bannerman (1963) has a good account of the havoc caused by capercaillie in nurseries and newly planted areas.
3 Others were slower to change. As late as 1979, in the agreement setting up Glen Tanar National Nature Reserve, the Nature Conservancy Council (a forerunner of Scottish Natural Heritage) classed capercaillie and black grouse as pests.
4 At closer range, both sexes reveal complex patterns. The cock is mainly dark grey with paler grey vermiculations, giving a slate-grey appearance. His lower head, chest, flanks, belly and tail are almost black, the chest with an iridescent green sheen, and the upper mantle and wing-coverts a warm dark brown. The dark plumage has white or pale grey markings on belly, flanks and tail. A white shoulder spot stands out when he displays, its message mysterious. White streaks and spots on the main tail-feathers make tail patterns as individual as fingerprints. Some authors claim that individual patterns recur moult after moult, although others dispute this.
Hens are rufous-brown on the back, paler below, with much individual variation. The brown back is densely barred with buff or blackish. The broader barring on the underparts includes buff, blackish and varying amounts of white. Barring is usually absent across the orange-buff breast, making the distinctive patch. The tail is barred rufous and dark brown, varying from mostly rufous to mostly brown.
Höglund (1956) distinguished newly hatched males and females by bill colour, but this has not been demonstrated in Scotland.
5 Desmond Dugan, pers. comm. 2003.
6 At small leks, mature cocks seem to occupy territories. In the ‘piece of pie’ model, each established cock has a spring territory that is shaped like a wedge of pie, the thin end containing his stance. In continuous habitat, leks are typically some 2-2.5km apart, the pie about 2km across.
There are many variations on the ‘piece of pie’, in accord with local topography, habitat distribution and disturbance. At several Scottish leks, cocks display among trees along each side of a track, so the lek takes a linear form. Larger leks can have more than one centre of activity and may cover up to 1km2.
Studies of radio-tagged birds in Fennoscandia, central Europe and northern Russia (Storch, 2001) confirm that adult cocks have spring home ranges centred on the lek. In Fennoscandia, home ranges were more or less exclusive, whereas in central Europe and Russia they overlapped but cocks avoided each other. Overlapping was greater on bigger leks. Spring spacing behaviour does not seem to limit the number of cocks at a lek (Wegge et al., 2003). In short, it seems that cocks avoid each other around the lek, but do not have territories with defended boundaries, and so at high densities their ranges overlap.
7 The average number of cocks at seven leks in the Ilexa basin in 1981-6 and in 1988 was 24, with a range of 10-70 (Borchtchevski, 1993).
In the Pinega na013-chapter6 in 1986-2003, the average number of cocks at 5-13 leks varied from 3 to 12 (A. V. Sivkov, pers. comm. 2004).
8 The area of ground in which an animal lives.
9 Jones, 1982a.
10 James Oswald & Anneke Stolte, pers. comm. 2004.
11 Leks are often in the same place decade after decade, although some shift. Near Banchory in Deeside, an isolated lek of about four cocks moved a full kilometre between the late 1980s and the early 2000s, although individual cocks were occasionally heard singing at the old site up to spring 2004. Observations in Glen Tanar showed how this might happen. Over several years, a lek with about ten cocks and a single centre of activity developed a separate centre about 300m away, presumably comprising younger cocks. For a few years, both centres coexisted while the number of cocks declined at the original centre and increased at the new one. Cocks commuted between the two. Eventually, the original site became disused and the new site held all the activity.
12 Although Moss & Lockie (1979) reported that capercaillie song contained infrasound (noise below the threshold of human hearing), Lieser et al. (2005) were unable to detect this. Over the years, RM had three conversations with the late Ingemar Hjorth about infrasound in capercaillie song. In the first two, IH said that he could not find any infrasound. In the third, he said that he had been able to record it, but only at very close quarters, so this may be part of the answer. Moss & Lockie (1979) recorded only at close range (10cm), so contrary to their original suggestions, the sound may be audible only at close range. After the original paper was published, RM, like many other people, actually heard the upper reaches of the sound that we called infrasound. In the third phase of their song, cocks make a low grumbling noise at the lower reaches of human hearing, audible when the bird is very close to a hide. In captivity, we used to have a tenor cock that was particularly audible in this phase. Ivor Lockie also made some accelerometer measurements, which confirmed that this cock was vibrating at low frequency while producing these notes. An observer could put his hand on the bird’s back while it was singing and feel the vibrations. In short, cocks certainly produce low-frequency sound that is not usually recorded in descriptions of the birds’ song. It may not carry very far, hence its main function may be to impress other birds close by rather than attracting them from afar.
13 One cock attacked a golden eagle that had just killed the rival with which he was fighting; it killed him too. See www1.nrk.no/nett-tv/klipp/116233 (as at 18 November 2007).
14 On one occasion, a hen with chicks behaved like a great skua. Flushed by trained dogs during brood counts, she circled round and flew at head height directly towards RM, grunting threats as she approached. Just in front of her target, she jinked upwards, missing his head by a foot or two. She then repeated this unusual distraction display from the opposite direction.
15 Special Protection Areas are sites of international importance, designated according to EU directives.
16 In a constant, closed (i.e. no movement in or out) population with 30 per cent annual mortality of adult cocks, young cocks will comprise at least 30 per cent of the population, and sub-adults (cocks in their second year) at least 0.3 x 0.7 = 21 per cent of the population. For example, 45 cocks were counted at 22 known leks in the Vosges mountains in 1998-9 (Poirot & Preiss, 2002). These included adults and sub-adults, but not young cocks. The count was then increased by 20, based on the observation that one-third of cocks that attend leks were typically undetected by standard counts. Another 25 cocks lived solitarily away from any lek. In this case, lek counts accounted for half the adult and sub-adult cocks.
17 This will vary according to local conditions. See, for example, ‘Snares’ on p.170.
18 In other words, to assume that recorded counts had the same distribution as the counts that would have been noted had similar ones been made at every lek in Scotland. In fact, most big leks were probably found, but more small ones might have been missed. If so, calculated proportions will be conservative, slightly underestimating true proportions.
19 Potapov & Flint, 1987.
20 Duriez et al., 2007.
21 Ibid.
22 Storch, 2000a.
23 Excluding open bog and water bodies. Vladimir Borchtchevski & Per Wegge (pers. comms 2004).
24 Storch, 2001.
25 Before agriculture, it is likely that they also used lowland forest bogs with sparse tree cover, and other natural forest opened up by events such as fire and wind-throw.
26 Pennie, 1950, 1951.
27 Anon., 1840; Pennie, 1950, 1951; Lever, 1977; Gilbert B. Stevenson, pers. comm. 2005. Thirteen Swedish cocks and 15 hens arrived at Taymouth Castle on the estate of the Marquis of Breadalbane in 1837 and a further 16 hens in 1838. Another five hens came from Atholl estate, survivors of a failed attempt to breed birds (of unknown provenance) in captivity (Stevenson). At Taymouth, ‘A part of the birds [six cocks and four hens] were turned out in the autumn of 1837, and part were kept in a house. In the year 1838, a brace only was reared by the keeper, but two fine broods were seen in the woods…In the spring of 1839, instead of attempting to rear any capercaillies…[Lord Breadalbane’s head keeper] placed the eggs laid by the birds in confinement in the nests of grey hens, who hatched them, and brought them up in a wild state.’ In 1839 the head keeper estimated that 49 young were hatched by greyhens, and 60-70 poults reared by greyhens and capercaillie combined. In 1862 there were said to be 1,000-2,000 birds on this estate alone.
The Swedish birds were procured from local people by the Welsh-born naturalist Llewellyn Lloyd, then resident near Venusberg, on behalf of his cousin the great brewer Thomas Fowell Buxton (subsequently knighted), who had proposed the project to the Marquis of Breadalbane while shooting on his estate at Taymouth. Fowell Buxton continued to import birds in subsequent years, and to sell them in unknown numbers (but exceeding 30 because, in a letter to Lord Breadalbane dated 19 November 1842, he offered to sell ‘some 14 or 15 brace of which I have still undisposed of) to unknown estates (Stevenson). Hence, the number of birds imported was well in excess of the approximately 50 brought to Taymouth in 1837-8.
28 Baines et al., 1991. So few were shot after the mid-1980s that bags became unreliable indicators of numbers.
29 Bigger bags, of up to 150 birds in a day, have been reported but are said to be erroneous (Gladstone, 1930, cited by Pennie, 1950, as Gladstone, 1922, but not in his reference list).
30 Based on data from Braemar village.
31 Based on constant repetition of an informed guess by an unknown source.
32 The 1992-4 estimate of 2,200 had 95 per cent confidence limits of 2,500-3,200 (Catt et al., 1998), the limits for the 1998-9 estimate of 1,100 were 500-2,000 (Wilkinson et al., 2002), and for the 2003-4 estimate of 2,000 they were 1,300-2,800 (unpublished result of Royal Society for the Protection of Birds survey, K. Kortland, pers. comm. 2004). Other evidence suggests that the real 2003-4 figure was closer to the lower confidence limit of 1,300 than to the central estimate of 2,000. We have rounded numbers to the nearest 100.
33 Birds from Finland were introduced to Dawyck near Peebles in 1930 (Pennie, 1950).
34 Climax forest is the last stage in an undisturbed forest’s succession.
35 Canopy cover 50-60 per cent (Moss & Picozzi, 1994).
36 Kirikov, 1947, 1970.
37 In the managed forest of Varaldskogen in southeast Norway, cocks and hens avoided forest with overstorey tree densities of less than 500 stems per ha, and cocks, though not hens, avoided densities of over 1,000 stems per ha (Gjerde, 1991a). But in Abernethy pinewood (Summers et al., 2004), the cocks were found in trees with an average density of 195 per ha (interquartile range 130-350) and hens in trees with an average density of 350 (interquartile range 200-565). Abernethy trees had much broader canopies than Varaldskogen ones. Stem density alone is an ambiguous measure of habitat quality, but while canopy cover is more important it is less often measured.
38 Gjerde & Wegge, 1989.
39 These generalisations about habitat structure for broods in Scotland are based mostly on unpublished observations made during counts with dogs by RM.
40 But not so steep as to hinder birds walking back uphill after disturbance.
41 Baines et al., 1994.
42 Although this seems obvious, there has been little formal study of the optimum structure of ground vegetation for capercaillie broods.
43 Bevanger (1995) estimated annual losses from flying into wires to be about 20,000 capercaillie in Norway alone, equivalent to some 90 per cent of the annual hunting harvest.
44 Moss et al., 2000b.
45 Baines & Andrew (2003) found that marking fences reduced capercaillie strikes by roughly a half.
46 Seven leks occurred in 116km2 in the Ilexa River basin, Russia (Borchtchevski, 1993), and 36 leks in 515km2 in the Pinega nature reserve, Archangel Region, Russia (A. V. Sivkov, pers. comm. 2004).
47 Six leks occurred in 42km2 (Per Wegge, pers. comm. 2004).
48 Moss et al. (2006) gave a median natal dispersal distance of 11km for 13 hens. Adding unpublished data for another two hens increases this to 12km.
49 Lodgepole pine proved a financial and silvicultural disaster, largely because British foresters did not recognise crucial differences between various strains of Pinus contorta, and planted vast areas of trees that fell over and grew twisted, unmarketable trunks. It is now being replaced by other species, although it still has a role as a nurse crop for Sitka spruce planted on heather moorland, where lodgepole pine is supposed to suppress heather and so prevent heather check in Sitka spruce. The FC, having subsidised the planting of this tree for decades, in the 1990s began to provide grants for removing it at the taxpayer’s expense.
A fast-growing species, Sitka spruce can be established on ground where browsing of seedlings by deer or rabbits prevents other species from growing. It supplies much raw material for pulp, chipboard and paper, but its timber is of poor quality and is now undercut in price by better wood from the Baltic and other eastern European states.
50 The FC is beginning to recognise that its very future is threatened by the financial losses made by its own plantations and by private, grant-aided ones. It is therefore starting to mention forests as ecosystems, not as mere timber plantations, and aims to provide a range of benefits in return for public investment. In many places, this welcome change seems more rhetorical than practical, and old practices continue largely unchanged. In other places, conservation benefits are beginning to emerge. These include nature conservation, notably in the Highland Conservancy and parts of the Grampian Conservancy where Scots pine is still grown. (A conservancy is an administrative region headed by a conservator.) The FC has begun to manage some of its own woods with capercaillie in mind, and capercaillie management is now a recognised component of some grant schemes.
51 Picozzi et al., 1996.
52 A counterargument is that wide spacing produces knotty timber of low value.
53 Moss et al., 2001.
54 For example, in Speyside on 15-16 January 1976, of nine crops from shot birds (seven cocks, two hens), six contained nothing but pine, but three cocks had heather (4, 10 and 30 per cent by volume), blaeberry shoots (1, 0 and 10 per cent, respectively) and bearberry leaves (0, 5 and 0 per cent). In general, cocks are seen on the ground in winter more often than hens.
55 In the Bavarian Alps, the birds seem to prefer silver fir to Norway spruce, and in Lapland they prefer juniper to spruce. Capercaillie in the west Carpathians, however, confound this generalisation by making Norway spruce their main winter food (Saniga, 1998), even though fir and beech are available.
The capercaillie that winter in deciduous forests at the southern extremity of the Ural ridge (Kirikov, 1970) must survive without conifers. Similarly, there are no indigenous conifers in the Cantabrian mountains of Spain, where the birds’ winter diet comprises leaves of holly or beech buds, and herbs (Storch, 2001).
56 Moss & Picozzi, 1994; Picozzi et al., 1996.
57 In Scots pinewood, capercaillie seem to prefer feeding in particular trees, which are often said to be diseased, damaged or on unsuitable soils. Needles from such trees contain more protein and less of the resins that serve as plant defences (Spidsø & Korsmo, 1994). In Norway, feeding trees were removed experimentally and birds then spent more time in other parts of the forest (Gjerde, 1991b).
In Scottish plantations, droppings often lie thickly under the heavier branches of trees by rides or at compartment edges, presumably because birds prefer thicker branches for roosting or feeding.
58 Borchtchevski & Gubar, 2003.
59 Vladimir Borchtchevski, pers. comm. 2004.
60 Summers et al., 2004; Watson & Nethersole-Thompson, 2006.
61 Picozzi et al., 1999.
62 Summers et al., 2004.
63 Storch, 2001.
64 Picozzi et al., 1996.
65 Moss, unpublished observations.
66 Imprinted captive chicks allowed to forage under natural conditions, however, took few caterpillars, choosing instead spiders, springtails, grasshoppers, beetles and especially ants (Spidsø & Stuen, 1988). Perhaps the eye of a well-fed and naive captive is attracted more to rapidly moving prey than to sluggish and cryptic caterpillars. In Scotland, chicks took many caterpillars when these were available in early June, but turned more to other invertebrates (ants, beetles, spiders, harvestmen and flies) when caterpillars pupated and became scarce in late June (Picozzi et al., 1999). In the central European literature, anthills are often assumed to be an important part of brood habitat. This might be because chicks use ants, or because anthills tend to occur in the same places as blaeberry, or because ants favour sunny, open sites that chicks also prefer for drying out after rain and for dust-bathing.
In the Pyrenees, capercaillie broods are often in herb-rich, grassy subalpine meadows with no blaeberry (Ménoni, 1990), where their invertebrate prey comprises largely grasshoppers (Emmanuel Ménoni, pers. comm. 2004). In Scotland, one brood spent much time in an open ride in a plantation, where the bulk of the chicks’ invertebrate food comprised click beetles and heather beetles (Picozzi et al., 1999). Their plant food, conventionally enough, was mostly heather and blaeberry. In a different plantation, another brood spent their first three weeks, to our astonishment, under closed-canopy Sitka spruce. In these dark conditions, there appeared to be hardly any growing vegetation to support the chicks or the invertebrates that they required. Tender new spruce shoots, however, lay in profusion on the ground, after unusually strong winds had broken them from the canopy. Subsequent analysis of the chicks’ droppings showed that they had been eating spruce needles, supplemented by weevils that often live in leaf litter.
The success of these novel Scottish diets remains an open question. The hen of the brood that ate click and heather beetles was killed by a predator when her still dependent chicks were 19 days old. The other hen successfully nurtured her chicks under closed-canopy Sitka spruce for three weeks, but then lost them after the brood left the wood for more open ground. Even so, both hens had successfully reared chicks on the same ground in previous years.
67 The vagueness of this last category requires explanation. The traditional method of studying diet involves killing birds and examining the contents of their crops. Such methods are now less acceptable, especially for endangered species such as capercaillie, and workers must examine droppings for identifiable remains of food items. This works quite well for invertebrates with hard parts, and for plants with cell walls tough enough to retain recognisable characteristics after digestion. But it is not so good for identifying tender summer herbs, the well-digested remains of which are classified as ‘miscellaneous’ and can form a large part of the chicks’ summer diet.
68 Black-billed capercaillie, the capercaillie species of northeast Asia, use Dahurian larch (Larix gmelinii, syn. dahurica) as a staple throughout the year. In winter, because larch are deciduous, the birds make do with twigs and buds. Our bird, the common or western capercaillie, also takes larch buds, flowers and needles as available in spring, summer or autumn. Larch is, however, often absent from their diet because it does not occur, for example, in large tracts of boreal forest with poor soils.
69 James Oswald, pers. comm. 1975.
70 Moss, 1980.
71 Moss & Oswald, 1985.
72 Moss, 1986.
73 James Oswald, pers. comm. 2004.
74 Moss et al., 2000b.
75 Storaas et al., 2000.
76 See Chapter 12 on how a hen’s diet affects her condition and the quality of her eggs and chicks. The evidence for red grouse and ptarmigan is based on experiment, while that for capercaillie (Moss et al., 2001) is correlative.
77 Picozzi et al., 1999.
78 Caizergues & Ellison, 2002; Warren & Baines, 2002.
79 Schroeder, 1985; Hines, 1986; Small & Rusch, 1989.
80 If patches of summer and winter habitat are mixed on a small, fine-grained scale, seasonal movements are likely to be short. If patches are large and distinct, on a coarse-grained scale, movements will probably be longer.
81 Kirikov, 1947.
82 Storch, 2001.
83 R.W. Summers & R. Proctor, unpublished internal report to RSPB.
84 Wegge & Rolstad, 2000.
85 Storch, 1994. Broods were tracked until late August.
86 Picozzi et al., 1999. Broods were tracked until late July.
87 Storch, 2001.
88 Moss et al., 2006 – see note 48.
89 Pheasant-capercaillie hybrids also occurred, and there are several reports of lustful hen capercaillie offering themselves to humans during the mating season. See www.youtube.com/watch?v=jgSSpMu9CNA for a video of a hybrid (as at 9 November 2007).
90 Ménoni, 1991.
91 Borchtchevski & Gubar, 2003.
92 Cramp & Simmons, 1980.
93 Siivonen, 1948.
94 As shown by Moss & Oswald (1985).
95 Borchtchevski, 1993.
96 However, stoats are less abundant in the more agricultural south than in the more forested north (see Chapter 13).
97 In the Pinega nature reserve (421km2), breeding success (about two young reared per hen) was no better within the reserve than in exploited forest outside (Borchtchevski et al., 2003). The exploited forest still had some unlogged patches of old-growth spruce forest. Capercaillie densities in August (about six birds per km2) were similar in old spruce forest within the reserve and on comparable unlogged patches outside. There was a greater density of capercaillie, however, in naturally regenerated young forest within the reserve than in young forest outside. Apparently, logging reduced capercaillie numbers because young forest after logging provided poorer habitat than natural regeneration after lightning fires and wind-throw.
At Pinega, signs of red fox were noted outside the reserve but not within it. Signs of pine marten and stoat showed a similar incidence inside and outside. More goshawks were seen inside, and more buzzards outside. The frequency of finding kills, and the proportion of kills attributed to mammals or to birds, was similar inside and outside. In a study at Pechora-Illych reserve, the densities of mammalian predators (red fox, pine marten, stoat) inside the reserve did not differ from those in logged forest outside (Beshkarev et al., 1995). In short, the evidence goes against the idea that logged forest necessarily supports more predators and poorer breeding success of capercaillie than virgin forest.
Observations on the Pechora-Illych reserve raised another possibility. Capercaillie densities decreased between the mid-1960s and the mid-1970s, for reasons largely unconnected with logging. Intensive logging began in 1970 and left two reserves of virgin forest, a smaller one of 158km2 surrounded by exploited forest, and, some 35km to the northeast, a large reserve of 7,055km2. The smaller reserve had become an island of undisturbed habitat set in a vast sea of logged forest. Capercaillie numbers recovered from the natural decline on the large reserve but did not recover on the smaller one. The authors suggested that density-dependent dispersal drained birds from the smaller reserve into the surrounding logged areas, so preventing an increase in the reserve. Just how big a reserve must be to prevent such dispersal is not clear. The observation that densities in old-growth spruce forest were no higher inside than outside the Pinega reserve (see above) raises the alarming possibility that a virgin patch of 421km2 was insufficient to maintain capercaillie densities when surrounded by degraded habitat.
98 The Onega-Pudoga massif in northern Russia comprises about 5,000km2 of virgin forest surrounded by logged areas where the density of capercaillie is some three to four times lower. Data from a 650km2 study area within the virgin massif suggested that many young birds left for the lower-density logged areas, and that some later returned as adults (Borchtchevski, 1993). Similar conclusions were reached, on the tiny Scottish scale, for the remnant Caledonian pinewood in Glen Tanar (Moss & Oswald, 1985), which covers about 12km2 and lies adjacent to plantations. Here, the evidence suggested the occurrence of density-dependent emigration of young hens mostly in their first winter, and of young cocks mostly in their second year.
99 Segelbacher et al., 2003.
100 The Scottish capercaillie population looks very much like a metapopulation, although, in hard scientific terms, there is not enough evidence to say that it has all the attributes of a theoretical metapopulation. Were we to wait for such evidence without taking action to safeguard them, the birds would probably become extinct. Our informed guess is that, by acting as if the birds do form a metapopulation, forest managers have the best chance of keeping them going.
101 S. B. Piertney, K. Kortland, F. Marshall, G. Segelbacher & R. Moss, unpublished manuscript.
102 An immediate problem, however, is that dispersing youngsters suffer heavy mortality by flying into fences. The removal and marking of fences have been done mostly on designated Special Protection Areas that are small relative to the distances moved by dispersing capercaillie. More youngsters would survive if more fences were removed, not only on Special Protection Areas but also in woods between them.
103 Grant, 1941.
104 Replanting of woodland on a large scale began in the mid-eighteenth century, too late to provide mature trees that would benefit capercaillie.
105 The greenhouse gases methane and carbon dioxide are released by agriculture and associated deforestation. It has been claimed that anthropogenic global warming, estimated after allowing for climatic fluctuations due to variations in the orbit of the earth around the sun, may have been occurring for 8,000 years (Ruddiman, 2003). During the last 2,000 years, warming has been briefly reversed by three periods of global cooling, which intriguingly followed the three biggest known periods of plague that have devastated human populations in various parts of the world. After each plague, much agricultural land reverted to forest, removing carbon dioxide from the atmosphere. The Little Ice Age was associated with bubonic plague in Europe and Russia (1499-1720), and the epidemic of smallpox and other diseases that reduced the population of the Americas from roughly 50 million to less than 10 million after Europeans arrived (1492-1680s). It is therefore just possible that the European invasion of the Americas contributed to the extinction of capercaillie in Scotland.
106 Declines during the Second World War, however, occurred also in black grouse, which do not depend upon mature forests, and in red grouse and ptarmigan, which do not live in forests at all. More generally, there was a widespread decline of grouse and other animals in much of northern Europe, from Scotland through Norway to the Ural mountains, including widespread declines of red grouse and willow ptarmigan, rock ptarmigan, capercaillie, black grouse and hazel grouse around 1939, and low numbers in the early 1940s (Siivonen, 1948; see also Chapter 3 for more on this). Hence sudden climatic change as well as habitat loss probably contributed to the large decline of capercaillie associated with the Second World War, not just in Scotland but in much of northwest Europe. Numbers in Scotland increased in the 1960s and early 1970s, but then there began the decline that lasted at least until the end of the century.
107 Moss et al. (2000b) give the wide confidence limits associated with these statements about breeding success.
108 The median is the middle item in an ordered list.
109 The general decline was not apparent at Glen Tanar at this time. Indeed, this core population seems to have been exporting birds during this period (Moss & Oswald, 1985), a likely example of density-dependent dispersal.
110 Moss et al., 2000b; Moss, 2001.
111 Baines & Andrew, 2003.
112 Deer and Fencing, Forestry Commission Guidance Note 11, accessible at www.forestry. gov.uk/pdf/DeerFencingguidancenote11.pdf/$F ILE/DeerFencingguidancenote11.pdf (as at 3 November 2006).
113 In the late 1990s, Scottish Natural Heritage (SNH) were making it plain that capercaillie conservation was a low priority with them. Following public outcry, a petition (PE16) to the Scottish Parliament organised by James Oswald, and a complaint (2000/4304) by RM to the European Commission (EC), the Scottish Executive and SNH, made about £750,000 available for removing and marking fences in 2000. Also, SNH together with the FC and the RSPB made successful application to the EC for LIFE funds totalling about £5 million for capercaillie conservation. This five-year programme began in 2002.
114 White et al., 2000. Snares are banned in all but five EU countries, the others being Ireland, Belgium, France and Spain. In all these four countries, regulations are more stringent than in the UK (Scottish Executive Consultation on Snaring, November 2006).
115 Cosgrove & Oswald, 2001.
116 A drive count involved a line of beaters walking noisily through a block of woodland and flushing birds towards a line of counters, who stood outside the block. The area covered changed slightly in 1990, from 4.1km2 to 4.4 km2, but this does not affect the conclusion that the sex ratio changed. There was no count in 2001.
1 Hjorth, 1970; Cramp & Simmons, 1980; Johnsgard, 1983; Lindström et al., 1998; Storch, 2001.
2 Nethersole-Thompson & Nethersole-Thompson, 1939; Watson & Jenkins, 1964.
3 Rusch & Keith, 1971; Jamieson & Zwickel, 1983.
4 MacDonald (1970) illustrated air sacs in a male rock ptarmigan’s throat, including an inflatable walnut-sized membrane. All grouse species share with domestic fowls two inflatable air sacs, the walnut-sized one being extra. A loop in the cock capercaillie’s windpipe makes the windpipe a third longer than the neck (Johnsgard, 1983). These features and drum-like membranes on the windpipe affect resonance (prolonging a sound by vibration) and frequency. Air spaces in the bones may help, for the whole body of a displaying cock grouse heaves with vibration. Grouse can call at much lower frequencies than those produced by organpipes of the same length, like blowing across the mouth of a laboratory flask (Helmholtz resonator).
5 Watson & Jenkins, 1964; Watson, 1972; Cramp & Simmons, 1980; Wike & Steen, 1987; Martin et al., 1995.
6 Pedersen et al., 1983.
7 AW noticed this at Lofoten in 1950, and in 1951 when Douglas Scott and Tom Weir agreed (Weir, 1953). Norwegian birds call in a higher key than red grouse (Chapman, 1897).
8 For example, Cramp & Simmons, 1980; Thaler, 1983.
9 International Phonetic Association, 1963.
10 Original transcriptions are in Watson & Jenkins (1964) and Watson (1972).
11 Watson, 1972; Cramp & Simmons, 1980; Thaler & Neyer, 1983.
12 Watson & Jenkins, 1964; Watson, 1972.
13 Watson, 1972.
14 Moss, 1972a; Watson, 1972, unpublished; Olpinski, 1986; Parr et al., 1993.
15 Watson & Jenkins, 1964; MacDonald, 1970; Watson, 1972.
16 Parker, 1981b. The average is 7.8 days, and the range 3-14 days.
17 Brockie, 1993, p.124.
18 Watson & Jenkins, 1964.
19 Nelson, 1887; Watson & Jenkins, 1964; Watson, 1972. The mean nearest-neighbour distance of willow ptarmigan in snow-burrows was 2.1m (Mossop, 1988).
20 MacDonald, 1970.
21 Moss et al., 1972; Savory, 1974.
22 Rae, 1994.
23 Gardarsson & Moss, 1970.
24 Watson, 1963b.
25 Gordon, 1915.
26 Holder & Montgomerie, 1993a; Pedersen et al., 2006; Watson, unpublished.
27 Savory, 1978.
28 Gelting, 1937.
29 Watson, 1966, unpublished.
30 Ellison, 1966; Pendergast & Boag, 1970.
31 The latent heat required to turn 1g of snow at 0°C to water at 0°C is 80 calories, which is almost as much as the 100 calories needed to raise 1g of water from freezing point at 0°C to boiling point at 100°C.
32 Watson, 1972. Scottish ptarmigan snow-bathe at all seasons. See also photographs of captive Austrian birds in Thaler (1983).
33 Mercer & McGrath, 1963.
34 Storch, 2000a.
35 Savory, 1978.
36 Watson & Jenkins, 1964.
37 Robel, 1969.
38 Parr & Watson, 1988.
39 Storch, 2001.
40 A pack is a ‘Number of hounds kept together for hunting, or of beasts (esp. wolves) or birds (esp. grouse) naturally associating’ (Concise Oxford Dictionary, 3rd edn, 1953).
41 Bent, 1932; Kessel, 1989; Campbell et al., 1990. AW counted 950 in a pack on Badalair at Glen Esk on 13 January 1959, and with his father and Tom Weir he counted 1,000 on Carn Aosda near the Cairnwell on 1 January 1965. Deep drifted snow covered low and high ground on both occasions.
42 Watson, 1963b.
43 Dementiev & Gladkov, 1952; Potapov & Flint, 1987.
44 Watson, 1972, unpublished.
45 Watson, 1972.
46 Millais, 1909.
47 Photograph in Steen, 1989, p.296, showing hatched eggshells around the nest. A greyhen with downy chicks died in a fire near Inverness (Bannerman, 1963).
48 Stuart Rae & Watson, unpublished. On Cairn Gorm above 1,140m, Rae found a hen lying dead on her eggs on 24 June, and AW found another the following day. Heavy snow fell on 6 and 7 June, and many drifts lasted until 11 June.
49 Sandercock, 1994.
50 Watson & Jenkins, 1964; Watson, 1972; Martin & Horn, 1993; Hannon et al., 1998.
51 Macpherson & McLaren, 1959.
52 Marcström, 1986.
53 Sonerud, 1988.
54 Thaler, 1983. Included here are photographs of a hen ptarmigan standing while brooding.
55 Watson & Jenkins, 1964.
56 Watson, unpublished.
57 Watson, unpublished, recorded at Glen Esk. Most adults were back-tabbed, and the location, number and age of young were known for each brood before shooting. When families regrouped after shooting, he saw which had lost parents or young, and how many. Another observer noted tabbed birds shot in the bag.
58 Watson, unpublished.
59 Weeden, 1965b.
60 Gardarsson, 1988.
61 Watson, unpublished.
62 Watson unpublished, recorded at Glen Esk with red grouse, and at Beinn a’ Bhuird and Glas Maol with ptarmigan.
63 Watson, 1972.
64 Martin, 1984; Holder & Montgomerie, 1993a; Hannon et al., 1998.
65 Brodsky, 1988a.
66 Allen, 1977.
67 Watson & Jenkins, 1964.
68 Ibid.
69 Watson, 1972.
70 Moss, unpublished. Incubating hens flushed at a distance of several metres, without distraction display.
71 Jenkins et al., 1963.
72 Hudson & Newborn, 1990.
73 Pedersen & Steen, 1985; Martin & Horn, 1993. At Churchill, Canada, hens in good condition before incubation took greater risks when defending nests.
74 Pedersen, 1989.
75 Hannon, 1984. Hens with a polygamous cock suffered a bigger rate of nest losses than hens in monogamous pairs, and a smaller percentage of them returned the following year.
76 Martin & Cooke, 1987.
77 Pedersen, 1993.
78 Martin, 1989. We wonder whether these cocks might have been related to the hens, and though not fathers to the chicks, might perhaps have been uncles.
79 Unander & Steen, 1985.
80 MacDonald, 1952; Weeden, 1965b.
81 Freuchen & Salomonsen, 1960.
1 Large animals have small surface areas relative to their volume, and so lose less heat per unit of volume. This often applies to races within species, and is the basis of Bergmann’s rule that big races live further north.
2 Sulkava, 1969; Zonov, 1983. Finnish redpolls dropped into snow and one penetrated 25-30cm within ten seconds.
3 Formozov, 1964; Johnsgard, 1983. For Britain see Pennant, 1771; Chapman, 1889, 1924; Bolam, 1912; Gordon, 1912 (photograph), 1915; Vesey-Fitzgerald, 1946; Watson, 1952, 1956, 1963b, 1972; Watson & Jenkins, 1964.
4 E. Pontoppidan, 1755, Natural History of Norway, cited by Chapman, 1924.
5 Pennant, 1771.
6 These species therefore do not fit Bergmann’s rule.
7 Watson & Jenkins, 1964; Watson, 1972.
8 Watson & Moss, unpublished.
9 Gordon, 1915. ‘Sometimes my old footprints were taken possession of by the ptarmigans as night-quarters’ (Manniche, 1910).
10 For example, Nelson, 1887; Bent, 1932.
11 Roald Potapov, pers. comm. 2005.
12 Marjakangas, 1986.
13 Moss, in Watson, 1972, and unpublished.
14 James McIntosh, Dave Patterson and others, pers. comm. 2005.
15 Watson, unpublished, at Glen Esk, Kerloch and upper Deeside. Checks with dogs revealed birds underneath. Heather at roost sites showed freshly bitten shoots, so birds ate while underneath. Light penetrates up to 50cm in dry snow (McKay et al., 1970, citing G. D. Rikhter, 1963, Problemy Severa 7, 85-9).
Chapman (1889) noticed that red grouse vanish after snowfalls and are under the snow. Bolam (1912) wrote, ‘shot seven grouse in rapid succession and without moving a yard…out of perhaps fifty “bolting” from their burrows around me’.
16 Moss, unpublished, at Kinveachy.
17 Butler, 1917. This was in 1912.
18 Watson, 1963b, 1965a. He never found Derry Cairngorm completely deserted of ptarmigan, as icy conditions affected only a band of altitude, with softer snow at higher or lower altitudes.
19 Koskimies, 1958; West, 1968, 1972; Korhonen, 1980.
20 Gates, 1962; Brander, 1965; Gullion, 1970.
21 Thompson & Fritzell, 1988; Swenson & Olsson, 1991. At air temperatures below -4°C, hazel grouse dig snow-burrows. On days of hard frost and insufficient snow, they roost 3.8m up in trees, favouring small spruces with a great depth of foliage above and around the roost site.
22 Mossop, 1988.
23 Gullion, 1970.
24 Pruitt, 1958.
25 Watson, unpublished. Also in northeast Greenland, rock ptarmigan roosting in open bowls were often ‘frightened out of their holes’ (Manniche, 1910) by Arctic foxes and ermines whose tracks were easily seen on newly fallen snow, but he saw no sign of any being caught. Birds disturbed from underneath powder snow fly in ‘an explosion of snow-dust’ (Semenov-Tyan-Shanskiy, 1960, Fig. 6), which probably distracts predators.
26 Formozov, 1964; Spidsø et al., 1997.
27 Gullion, 1970.
28 Andreev, 1978, 1980.
29 Watson, 1966.
30 Manniche, 1910; Watson, 1972.
31 Watson, 1972, Fig. 7.
32 Watson, 1972.
33 Watson & Jenkins, 1964.
34 Watson, unpublished.
35 Marjakangas, 1986, 1990. The 1986 paper is the most detailed study of snow-roosts in grouse.
36 Semenov-Tyan-Shanskiy, 1960.
37 Höglund, 1980.
38 Manniche, 1910; Bent, 1932; Gelting, 1937; Freuchen & Salomonsen, 1960; Irving, 1960; Watson, 1972. Birds in northeast Greenland make open roosting bowls in frosts often down to -40°C, and sometimes at -45°C.
39 Marjakangas, 1986.
40 Marjakangas, 1990. At air temperatures of -3°C or above, snow-roosting ‘may not be necessary’ for saving energy.
41 Marjakangas, 1986.
42 Ibid.
43 Andreev, 1991.
44 Andreev, 1980.
45 Andreev, 1978, 1980.
46 Mossop, 1988.
47 Gelting, 1937.
48 Marjakangas, 1990.
49 Bent, 1932.
50 As described by Mossop (1988):
The fox’s hunting method seemed most dependent on its ability to accurately locate a snow-roosting bird. In each instance the fox failed for essentially the same reason: the bird that was first flushed was not the bird being stalked. The fox’s stalk or rush always took it past a bird it was apparently unaware of. The synchronous and contagious flushing of ptarmigan from snow-roosts may also startle foxes. During one observation a fox stepped on a snow-roosting bird. The bird bursting from underfoot and the flushing of the rest of the flock visibly shook the fox, which made no attempt to grab at any of the birds.
51 Olaf Hjeljord, pers. comm. 2004.
52 Weeden, 1965a.
53 Freuchen, 1961.
54 Eric Pirie & John Pottie, pers. comm. 2006. Pirie is an instructor at the National Mountaineering Centre at Glenmore Lodge near Aviemore, while Pottie is an experienced cross-country skier. Two men take two-and-a-half hours to dig a hole in fairly compact snow in the Cairngorms (Pirie). Digging is faster in soft snow, but the hole must be made bigger to prevent the roof sagging, so the overall time needed differs little. Four people, including Pottie, took two to three hours at a snow bank to make a hole tall enough for standing inside, and he and another skier took one-and-a-half hours to dig sideways into a bank. Once when he found no bank during the evening of a lone ski tour, Pottie took 30 minutes to cut snow blocks on level snow with a ski and then dug a trench on their lee side. Drifting snow soon covered him, but his warm breath kept open a chimney above his head and he slept for eight hours.
1 Peterle, 1955; Watson & O’Hare, 1979b.
2 Watson & Jenkins, 1964; Martin et al., 1990.
3 ‘Pairing’ means staying together, not just being in brief contact.
4 Moss & Watson, 2001.
5 On Hrisey in Iceland, some hen rock ptarmigan maintained separate home ranges, each overlapping with a few male territories and involving inter-hen aggression (Gardarsson, 1988). This was associated with heavy losses of territorial cocks to gyrfalcons, and semi-promiscuous mating.
6 Hannon, 1983.
7 MacDonald, 1970; Olpinski, 1986; Holder & Montgomerie, 1993a.
8 MacDonald, 1970.
9 Watson, 1963b, 1972, unpublished.
10 Watson & O’Hare, 1979b; Pedersen et al., 1983; Watson, unpublished.
11 Watson & Jenkins, 1964; Watson, 1972.
12 Eason & Hannon, 1994.
13 MacDonald, 1970.
14 Moss, 1972a.
15 Brodsky & Montgomerie, 1987.
16 Moss, 1972a; Watson, 1972. In one case in Alaska, after a long chase the subordinate was physically untouched but so petrified that he remained motionless as RM picked him up from the ground. When gently tossed into the air, he fell to the snow-covered ground, making no attempt to fly.
17 In Alaska, for instance, RM observed one such case with willow ptarmigan in spring. The hen of cock A walked into the territory of cock B, where she was courted by him. Cock A then followed his hen, whereupon cock B attacked cock A but was beaten in the ensuing dispute. After that, A’s territory included the disputed ground that had formerly been cock B’s. In Scotland, AW has often seen changes in territorial boundaries with red grouse and ptarmigan, especially in autumn when boundaries have only recently been established and are still fluid (Watson, unpublished). The autumn situation in Scotland is comparable with the Alaskan one observed by RM, both occurring at the start of the new territory establishment. In Scotland, AW observed another set of cases with both species during years of cyclic population decline, when many territorial cocks gave up their territories in spring and this again induced a temporarily fluid situation with regard territorial boundaries.
18 Other papers presented territory maps but not data on territory size (Watson et al., 1984a; Hudson, 1992; Moss et al., 1994).
19 Palmer & Bacon, 2000.
20 Watson & Miller, 1971.
21 Watson & Miller, 1971; Watson et al., 1984a; Moss et al., 1994; Palmer & Bacon, 2000; and published maps therein.
22 Jenkins et al., 1961, 1963; Watson & Jenkins, 1964; Watson & Miller, 1971. ‘It was possible to measure territory size exactly, by plotting where neighbouring cocks paraded close together at the boundaries. Sufficient parades were seen to delimit the entire boundary on many territories and most of the boundary on others’ (Watson, 1967b). On Dovrefjell, Pedersen (1984) mapped territories to the nearest 2m on ground with landmarks and to 10m on ground with few landmarks, even though territorial calling was confined to dawn and dusk (Pedersen et al., 1983).
23 Hannon, 1983; Unander & Steen, 1985; Gardarsson, 1988; Rae, 1994.
24 MacColl, 1998; MacColl et al., 2000.
25 Chapman (1924) wrote, ‘ere daylight is fairly established we have half the grouse for a mile around exactly located; almost they advertise their addresses!’
26 Lance, 1977; Pedersen, 1984; Watson & Moss, unpublished.
27 Watson & O’Hare, 1979b. For example, two observers who hear a call at the same time can compare notes later and find the approximate location by extending the lines for the two directions until they meet.
28 Jenkins et al., 1963; Watson, 1965a; Watson & Miller, 1971.
29 AW lived 6km from the Glen Esk area, and at Kerloch 4km from the study area in the first year but later less effectively 11km away in a valley out of sight where weather often differed. Kerloch’s bigger bogs, more numerous boulders and taller heather afforded worse access for vehicles, and the area was less concentrated, entailing more time driving between different sections and more effort to mark birds. Hans Pedersen and Johan Steen lived in a hut in the middle of their Dovrefjell area.
30 Watson, unpublished.
31 Jenkins et al. (1961) include examples of case histories at Glen Esk:
One cock lived within another’s territory for a week without being expelled; he was evidently a submissive bird because whenever the owner appeared he crouched low with his comb invisible and then looked very like a hen. When the owner was away, this intruder occasionally threatened other intruders, and then he raised his comb and looked like a cock; but eventually he was expelled by the rightful owner.
Where the owner is replaced, prolonged conflict goes on for days or even for weeks until the situation becomes stabilised again. In one case the previous owner C had always had a hen, and cock D that replaced him had always been unmated in a territory a few hundred yards away, beyond another mated cock’s territory. Within two days of C’s disappearance, D had deserted his territory, occupied C’s territory, and paired with C’s hen…D’s previous territory was now occupied by the three neighbouring cocks and also by a fourth cock E that had been trying to live within another cock’s territory half a mile away. Within this other territory E had been silent, rarely showing his comb, and creeping away into cover as soon as the owner appeared. But as soon as E arrived in D’s old territory his behaviour changed completely; he showed his comb and threatened vigorously as other cocks came near, and flew at the others and fought vigorously with them. He soon drove his neighbours back, defined new boundaries around a territory similar in size to that of D, and within a few days he had paired with the hen from one of his neighbours. On one day he had hens from two of his neighbours. It was remarkable to watch how the behaviour of this previously very submissive cock changed as soon as he found a vacant piece of ground.
In another case a vigorous cock F that had previously always had a hen became injured on one eye. He at once became quiet, spent much time resting in his territory, and the hen left him almost immediately. Within two days the three neighbouring cocks were advancing well into the territory, without being strongly threatened. On the third day the owner F was found unable to fly and looking ill. later that afternoon two neighbours G and H had a fierce boundary dispute right in the middle of F’s old territory, on his favourite sitting place. Meanwhile F was feeding only a few yards away, looking very subdued and hen-like. Next day G saw F and becked very loudly, landing only five yards away. Thereupon F crouched for 20 minutes, with his head touching the ground and moving not a feather, while G cackled loudly and strutted around apparently searching for F. F did not recover until long after G had flown away. The same day, F was seen panting and unable to fly, and looking very ill while being attacked by H. He then disappeared and has since been found dead on nearby communal ground. Long before this it was obvious that G and H had completely occupied F’s territory, and that F now had the same status as a bird living within another’s territory.
32 MacColl, 1998; Lock 2003. Watson & Moss (1971) distinguished birds such as E (see endnote 31) as Class 2 ‘non-territorial residents’, which ‘lived mainly on the moor, but were submissive to the territorial birds and were often chased by them out of the territories on fine mornings, when territorial behaviour was most vigorous’, but ‘were free to feed on the moor for most of the day’ and ‘on windy, snowy or heavily-overcast mornings’. Class 3 birds were ‘non-territorial transients’, which moved around more, ‘suffered heavy mortality, and hardly any were left by January’. ‘During fine calm weather, usually in January or February, there was a sudden change and territorial behaviour went on all day. Following this increase in territorial behaviour, Class 2 grouse were now forced off the moor to marginal habitats on scrub and fields where they were seldom attacked by territory owners. The resident population on the moor suddenly decreased due to the departure of the Class 2 birds’.
33 Jenkins et al., 1961, Fig. 6; Watson, 1967b. Watson (1970) says that in autumn one sees ‘a psychosomatic effect after a territorial cock is ejected from its territory. It suddenly becomes much less aggressive, no longer courts hens, and spends prolonged periods resting and hiding. Such birds rapidly lose condition and may die within a week, even though other non-territorial birds are able to feed freely anywhere on the moor.’
34 Watson, unpublished.
35 Watson & O’Hare, 1979b; Pedersen et al., 1983. The threshold is roughly 25 territorial cocks per km2 (Watson, unpublished). An exception is that cock red grouse and Scottish ptarmigan at low density do beck when fog or falling snow restricts visibility. While burning heather in sunlight, we often heard cock red grouse becking in the smoke. Perhaps they felt safe to beck, because predators could not see them. White-tailed ptarmigan also confine calling to dawn and dusk, except in fog or falling snow (Schmidt, 1988).
36 Pedersen et al., 1983.
37 Gordon, 1920.
38 Witherby et al., 1944.
39 Watson & O’Hare, 1979b.
40 Unander & Steen, 1985. Perches were ‘often ant-hill like hillocks, 0.2-1.0m high and with a base diameter of 0.2-i.om. Dissection showed them to consist almost solely of old ptarmigan droppings, originally on a rock’. Droppings decompose very slowly on such excessively drained sites in high-Arctic climates (Watson, unpublished), and ‘easily endure five years’ (Wynne-Edwards, 1952).
41 Williamson & Emison, 1969.
42 Watson, 1965a.
43 Myrberget, 1983.
44 Watson & Moss, unpublished.
45 Watson, unpublished. Being naturally fragmented, hilltops have more peripheral areas than moorland.
46 Watson & Jenkins, 1968; Watson & Moss, 1971. The earliest that young cocks took daytime territories was on 3 August, after removal of most old territorial cocks in an experiment. In August and early September, young cock red grouse and Scottish ptarmigan took temporary territories at dawn before returning to their broods (Watson & O’Hare, 1979b; Watson, unpublished). Broods of red grouse finally broke up between August and November, usually in late September or early October.
47 Bossert, 1980.
48 Harper, 1953; Bergerud & Mercer, 1966; Mercer, 1967, 1968.
49 Gruys, 1993. Using data on marked birds, he inferred that many juvenile cocks also took part.
50 Haftorn, 1971.
51 Pedersen, et al., 1983. Territorial calling began in the first week of September, when the oldest chicks reached 10-11 weeks. It peaked at about the start of November, before ceasing after mid-December when deep snow covered the area.
52 Johnsen (1953) found that during winter in northernmost Greenland the rock ptarmigan had tiny testes, much smaller than those in Scottish birds during winter (Watson, 1956, 1987b).
53 Gordon, 1912; Watson, 1965a.
54 An exception in Scotland can occur in late spring, when birds sometimes take temporary territories nearby on lower ground with less snow (see above in main text). If hens are already on nests when a deep snowfall occurs, however, the cocks do not leave their territories, as Gordon (1925) found in the Cairngorms on 29 May:
Each cock ptarmigan in spring marks out for himself and his mate a certain ‘territory’. But this great May snowfall, ruthlessly wiping out such ‘territories’, had caused considerable confusion in the ptamigan world, and no cock ptarmigan were at the moment in possession of those undisputed areas, which, under normal conditions, they should have had at this season. This was the explanation of the restlessness and excitement that filled the ptarmigan community of Coire Beanaidh this day.
He described many cocks in aerial becks, and also cocks displaying walking in line, sparring and chasing.
55 Moss, 1972a.
56 Ron Modafferi & Moss, unpublished.
57 For example, Watson, 1965a; Lance, 1978a; Erikstad, 1985a; Marti & Bossert, 1985; Unander & Steen, 1985; Gardarsson, 1988; Scherini et al., 2003. Rock ptarmigan differ from Lagopus lagopus in that many cocks desert their hens before the eggs hatch, especially on Arctic and subarctic lands.
58 Unmated cocks tend to pack in summer, and cock Scottish ptarmigan that have been paired in spring will often join these packs Cocks in the summer packs give ground calls and occasional becks at dawn and dusk, but often stay in the packs while doing so, or show brief becks or walking-in-line encounters nearby within 20 m.
59 Watson & O’Hare, 1979b; and Watson, unpublished (in Scotland).
60 One had bred successfully on the main study area, but after all cocks on a nearby smaller section had been removed experimentally, he took a territory there and later paired with a hen that subsequently nested there. The other was the sole old cock that we recorded as moving just before the nesting season, after being territorial and paired on a different part of the study area in the previous winter and summer.
61 Watson, unpublished. For example, in the case of 14 hens at Glen Esk, only ten stayed on the same areas. Four shifted to nearby territories, including three that switched cocks, even though their cocks from the previous year still held territories.
62 Schieck & Hannon, 1989; Hannon & Martin, 1996. In hens, 31 per cent shifted territory.
63 MacColl, 1998; Lock, 2003; Moss et al., unpublished manuscript.
64 Watson, unpublished. At Glen Esk in 1958-62, for example, there were 14 cases of marked hens being recorded in two successive years. Of these, ten were in the same area in the later year, eight of them paired with the same marked cocks as in the previous year, and two with new young cocks. Three hens had moved to adjacent territories that excluded ground used by them in the previous year, one being paired with a new young cock, and the other two shifting to adjacent old cocks even although their old partners were still present on territories. One young hen moved in the following year to a territory that lay immediately beyond the adjacent territory, and paired there with an old cock that had been there in the previous year, even though her first mate still had his territory, but was now unmated.
65 Hannon, 1983; Pedersen, 1984, 1988; Steen et al., 1985.
66 For example, Lack, 1966; Wynne-Edwards, 1986; Newton, 1994.
67 Moss et al., 1988.
68 Watson et al., 1984a.
69 Moss & Watson, 1990, 2001.
70 Lance, 1978b.
71 Miller & Watson, 1978.
72 Watson, 1964b; Watson & Miller, 1971.
73 In all studies, e.g. Svalbard, cocks with large territories are more likely to pair with two hens, as in red grouse (Watson & Miller, 1971). On any area in one year, cocks in poor habitat have larger territories with fewer hens than cocks in good habitat. In habitat of similar quality, aggressive cocks have larger territories and more hens than less aggressive cocks. On Derry Cairngorm, vociferous aggressive cock ptarmigan had large territories and paired with one or sometimes two hens, while adjacent, less aggressive cocks in the same habitat had small territories, seldom called, and were bachelors (Watson, 1965a).
In the study by Brodsky & Montgomerie (1987), ‘bachelors’ were smaller cocks with no mate or territory, and though resident neighbours had brief ritualised encounters, residents and bachelors had prolonged intense ones. Authors began observations in late spring (late May in this Arctic study) and described a bachelor as a cock usually on ground encompassing two or more paired cocks’ territories, and not seen regularly with a lone hen. No other study has found that all unmated cocks lack territories. It seems likely that bachelors had territories earlier in spring, but after late May it was better to stay near paired cocks in the hope of mating with a hen than to continue territorial behaviour further away. Also, many encounters seen by us between neighbouring mated cocks in Scotland, Iceland, Baffin Island and Alaska were not brief and involved attacks, as MacDonald (1970) also found on Bathurst Island.
74 Watson & Parr, 1981; Moss et al., 1994.
75 This statement has its limits, for at Rickarton there was evidence that food quality declined at high densities of red grouse (Moss et al., 1996).
76 Watson & Miller, 1971; Pedersen, 1984; Hannon & Dobush, 1997.
77 Unander & Steen, 1985; Olpinski, 1986.
78 Bart & Earnst, 1999.
79 Territory size was estimated without mapping the boundaries. Large territories had fewer hens, but also contained unsuitable habitat.
80 Steen et al., 1985. None of the four main vegetation types that were classified on the study area occurred on all the territories, so the authors suggested that a territory signalled a cock’s status more than what it offered in terms of food or shelter. In fact, however, what they showed was that none of the types was necessary for a territory, but they did not study what was offered by way of food or shelter.
81 Martin, 1991; Robb et al., 1992.
82 Hannon & Roland, 1984.
83 Miller & Watson, 1978.
84 Moss et al., 1988.
85 Watson & Parr, 1981.
86 Watson & O’Hare, 1979a; Watson et al., 1984a.
87 Miller & Watson, 1978.
88 Lance, 1978a.
89 For example, Lack, 1954, 1966; Wynne-Edwards, 1962; Watson & Moss, 1970; Newton, 1994. Wynne-Edwards (1986) argued that our work on red grouse backed his view on the importance of group selection in limiting numbers, but this was misinterpretation (Watson, 1987a).
90 Some authors recorded the presence of territorial birds, not their behaviour.
91 Watson, 1967a, 1985; Watson & Jenkins, 1968. Watson & Moss (1970) set out conditions necessary to show that territorial behaviour limits numbers. For autumn territorial behaviour to limit spring numbers, it is not necessary (Watson & Moss, 1990) that few or no territorial birds die or disappear over winter, although this did apply at Glen Esk, Kerloch (Watson & Moss, 1980; Watson, 1985), Rickarton (Watson & Moss, unpublished) and Glen Tanar (Moss et al., 1994). The necessary conditions are: the total number of birds in autumn exceeds that next spring; and the number of autumn territories is similar to that next spring. The owners’ identity is irrelevant.
92 Moss et al., 1994.
93 MacColl, 1998.
94 Hudson & Renton (1988) and Hudson (1990, 1992) misconstrued removal experiments by Watson & Jenkins (1968), and Hudson (1992) ignored criticisms (Watson & Moss, 1990) of his (Hudson, 1990) experiments. Park et al. (2002) stated that territorial red grouse in Speyside survived in early winter no better than non-territorial birds, and concluded, ‘territorial behaviour did not determine breeding density’. This was fallacious, because it is the number of territories that determines breeding density, not the owners of them. In principle, territorial behaviour can limit density even when territorial birds have lower survival rates over the winter than birds that are non-territorial in autumn (Watson & Moss, 1990).
Evidence reviewed by Watson & Moss (1990) showed that many territorial birds gave up territories and then died or disappeared in late winter during a deep decline at Kerloch in the 1970s (Watson & Moss, 1980, 1990), and heavy overwinter losses of territorial birds occurred in some years of decline at Glenamoy (Lance, 1976). Territorial behaviour in autumn nevertheless limited spring numbers at Kerloch in all years, and at Glenamoy in two years although not in three others, in one of which there were no young cocks present in autumn.
Park et al. (2002) used radio-tagged birds caught on four moors over eight years, the location of birds being checked at least once a week. They gave no data to relate their findings to populations, and did not map territories. None the less, their data are interesting in another respect. Along with our findings from the declines at Kerloch and Glenamoy, their data indicate that good survival of territorial birds over winter does not apply on all areas. At Glas-choille, Andrew MacColl and others found much turnover among territorial birds between autumn and spring, some of them being killed by predators and then replaced, and some moving to take territories elsewhere (MacColl, 1998). Territorial behaviour in autumn limited spring numbers, though the identities of many participants changed.
Hudson (1992) presented territory maps of red grouse at low density on a Speyside moor. He stated that much heather-dominated ground remained unoccupied in two springs, and that some that was unoccupied in one spring was occupied in the next. To him, this implied that territorial behaviour did not limit spring numbers. However, he gave no data on numbers or territorial behaviour before the spring, so the fieldwork was insufficient. For territorial behaviour to be limiting, birds do not need to occupy all ground (see ‘Territories on Poor or Peripheral Ground’ in the main text).
Hudson (1992) stated that critical evidence for ‘testing the importance of spacing behaviour’ was that ‘The population of grouse in spring should never exceed the number of territorial grouse in the previous autumn’. He counted grouse numbers in October on 20 study areas and again next spring, classifying pairs as territorial and also ‘single cocks that showed territorial behaviour’. In 18 out of 20 cases, territorial hens in spring outnumbered those in autumn, and likewise for territorial cocks in 12 out of 20 cases, thus ‘suggesting that spacing behaviour was not limiting their density’. Fieldwork was insufficient, however, because counts of grouse numbers cannot show reliably whether birds are territorial in October. Redpath & Thirgood (1997) counted calling cocks in October and the following April at Langholm, and the numbers of each sex. They studied overwinter survival of radio-tagged birds, whose status they judged as territorial if more than half the radio locations of a cock in October-December were within 25ha, and if a hen was paired with a cock on more than half the radio locations in October-December. Again, these methods were insufficient to judge status. The criterion of 25ha was an unsatisfactory surrogate of territory, because data confirming it were not presented. Calling cocks declined in number by 21 per cent between October and April, but there was no information about non-territorial birds.
95 Mougeot et al., 2003a, b, 2005c; Redpath et al, 2006a.
96 Lance, 1976.
97 Hannon, 1983; Mossop, 1988; Pedersen, 1988. Hannon did not know the origin of replacements, but this does not affect whether territorial behaviour limits spring numbers on an area. It involves other topics, such as the status of replacement birds before removals. Mossop found that 46 per cent of removed birds were replaced, all by birds that had been non-territorial. Both authors noted that replacement birds might have moved to take territories elsewhere if removals had not created vacancies. This also is not relevant to the question of whether territorial behaviour limits numbers on a given area, and instead involves other topics such as habitat quality on core or marginal areas, and migration.
98 Moss, 1972a.
99 Watson, 1965a.
100 Unander & Steen, 1985.
1 Cramp & Simmons, 1980.
2 Humphrey & Parkes, 1959. Criticism by Howell et al., 2003, and in Condor since.
3 Jacobsen et al., 1983. We judge autumn plumage as Basic, winter plumage as Alternate, and summer plumage as Supplemental, and moults to them as Pre-basic, Pre-alternate and Pre-supplemental.
4 Watson, 1972.
5 Watson et al., 1969.
6 Parr, 1975; Watson & Miller, 1976. Using the development of wing feathers and other plumage.
7 Flux, 1958; Semenov-Tyan-Shanskiy, 1960; Bergerud et al., 1963; Weeden & Watson, 1967; Braun & Rogers, 1971.
8 An after-shaft is a short feather that sprouts near the base of the main feather.
9 Höhn (1980) reviews the rosy flush. In willow ptarmigan, Bent (1932) reported a ‘beautiful faint pink flush…fades quickly after death’.
10 Salomonsen (1939) emphasised temperature, but it and snow-lie often coincide.
11 Barth, 1855; Bent, 1932; Mikheev, 1939; Murie, 1946; Höhn, 1980; Hannon et al., 1998.
12 Johnsen, 1929.
13 Ibid.; Mikheev, 1939; Novikov, 1939.
14 A follicle is a feather’s growth-point in the skin.
15 Parmelee et al., 1967.
16 Hewson, 1973; Watson, 1973; Stokkan & Steen, 1980.
17 Salomonsen, 1939.
18 Lorenz, 1904; Potapov, 1985, pers. comm. 2005. Coloured feathers grow in autumn, before the onset of cold weather.
19 Roald Potapov, pers. comm. 2005.
20 Salomonsen, 1939.
21 Watson, 1973; Jacobsen et al., 1983.
22 Elison, 1980; Jacobsen et al., 1983. Winters in Amchitka are almost as mild as at Braemar at 339m, below the Cairngorms. Amchitka’s coldest month has a mean temperature only slightly below freezing.
23 Hewson, 1973.
24 Watson, 1973.