Where and when Bittern is a localised breeding species, with currently c. 100 pairs, mostly in e. England and Somerset. It is more widespread in winter (mainly November to March) when numbers are augmented by continental immigrants, particularly in cold weather. They breed in extensive reedbeds but are often found in much smaller ones in winter. Night Heron is a vagrant mostly in spring (late March to June) but small numbers also occur in late autumn and occasionally in winter. It currently averages 14 records per year but is prone to irregular spring influxes, with as many as 61 in 1990.
Bitterns are habitat specialists, associated almost exclusively with reeds. They are most easily detected by the male’s low, far-carrying booming call, given in late winter and spring, not only during the day but also throughout the night during the peak of their activity. They are usually seen flying low over reedbeds (occasionally at some height) and in winter tend to be most active at dusk, as they fly to roost. They are, however, most easily seen in late spring, when the female has young and makes regular feeding flights. Severe winter freezes will also induce them into the open. Bittern is a large, owl-like heron, rich buff in colour, densely and intricately patterned with black. The most obvious and significant plumage features are the black crown, the black moustache extending back below and beyond the eye, thick black-and-brown lines down the foreneck and onto the breast, and owl-like black barring across the rich orangey-brown primaries and secondaries. It has a dull lime-green bill and legs, the latter longer than those of Night Heron, with the feet projecting well beyond the tail (note also Bittern’s remarkably long claws). They often fly with their neck stretched out, particularly after take-off.
Calls Occasionally calls in flight: usually a low kwok but in spring also a loud, gull-like caw.
Unlike Bittern, Night Heron is not a reedbed specialist but instead is likely to be found roosting in trees, particularly willows and alders, around the edges of lakes and marshes. As its name suggests, it is markedly crepuscular, flying out to feed at dusk (often at some height) at a time when other herons are going to roost. The first indication of its presence may be a loud, deep cok call, strongly reminiscent of a Raven Corvus corax. It is rather stocky and thickset, the head merging into the body when roosting. In flight it is compact with relatively short rounded wings. It has a thick pointed bill, a rather neck-less appearance and short legs, with only the feet projecting beyond the tail in flight (producing a short rear end). Juvenile With their black crown, mantle and scapulars, and pale grey wings and underparts, adults are easily identified, but juveniles are brown and much more Bittern-like. However, they are slightly but distinctly smaller and more compact than Bittern, with shorter legs. Their plumage is dark chocolate-brown, the upperparts profusely spotted buffy-white (each feather on the back, scapulars and wing-coverts having a buffy-white tear-shaped spot at the tip). The underparts are heavily but diffusely streaked. In flight, Night Heron lacks Bittern’s heavily barred, owl-like primaries; instead the primaries and secondaries are plain brown, with a white trailing edge and there are lines of buff-white spots across the tips of all the major feather tracts. Although adults have a black bill, the juvenile’s bill is initially dull creamy (with dark along the culmen ridge and cutting edge) gradually turning to yellow-green and then yellow. It has large orange eyes and blue-green or lime-green lores. The legs vary from dull green to bright greenish-yellow. First-summer A post-juvenile body moult usually begins in late winter, producing a plain brown or grey-brown back. By their first-summer, Night Herons have an intermediate pattern mirroring that of the adult’s, with the crown rather adult-like (but subdued), the back plain grey and diffuse brown streaking on the breast and neck-sides (they may even grow adult-like white plumes on the back of the head). However, the wings remain juvenile (spotted with white). The bill and legs begin greenish-yellow but the bill may start to turn black. Second-summer It seems that during the second half of their second calendar year (i.e. when just over one year old) they moult into a second immature plumage that is more adult-like, but uniformly brownish-grey across the back and wing- coverts with diffuse streaking on the neck (van Duivendijk 2011).
Covered here for the sake of completeness, American Bittern is a very rare vagrant (41 records, but just nine in 1950–2010). It usually occurs in western areas in November, sometimes remaining into winter. Slightly smaller than ‘Eurasian’ Bittern and easily identified in flight by plain black primaries and secondaries with an obvious broad chestnut-buff trailing edge to the wing. The wing-coverts appear contrastingly sandy. The crown is brown (not black), with a noticeable pale buff supercilium, a dark orangey-brown rear face, a long black moustachial stripe (reaching down to the neck-sides) and long, heavy, rich chestnut stripes down the foreneck and onto the breast.
Reference van Duivendijk (2011).
Where and when Purple Heron Ardea purpurea is a vagrant with records from March to November, but mostly in April and May. It currently averages 22 records a year with a peak of 35 in 1987. It occurs mainly along coasts of e. and s. England. A pair bred in Kent in 2010.
Habitat and behaviour Much more dependent on reeds than Grey Heron A. cinerea. Secretive and often very difficult to detect as it stands motionless at the edge of the reeds. Unlike Grey, it often lands on the tops of reeds or in trees and bushes within reedbeds.
Size and structure Distinctly smaller, slighter and ‘scrawnier’ than Grey Heron, lacking its obvious bulk (about 10% smaller in size and about 20% smaller in weight). At rest, it has a remarkably thin, snake-like neck as well as a strikingly long dagger-like bill that seems to merge seamlessly into its rather small head; its bill is much longer than that of Grey Heron. In flight, the folded neck forms a prominent low-slung ‘neck pouch’ that is obvious even in a back-on view. Befitting a lighter bird, its wings are slimmer and less rounded, resulting in a lighter, less lumbering flight with a tendency for vertical body movement during the down stroke. Also obvious are very large and conspicuous orangey-yellow feet, with very long toes reaching conspicuously beyond the tail.
Plumage Adult Easily identified by its solid black crown and striking reddish-brown neck, with a long thin black stripe that extends from below the eye to the bend of the wing. There are further black stripes on the front of the neck, but most distinctive is a narrow black ‘connecting stripe’ from below the eye to the upper nape, where it meets the crown and nape plumes. The upperparts are a darker, slatier-grey than Grey Heron, the contrast between the wing-coverts and the primaries/secondaries being much less obvious. There is a dark purple patch at the bend of the wing and a dark purple belly and thighs. Elongated brown scapulars and a brown cast to the wing-coverts combine with the chestnut-brown neck and dark purple areas to create a much browner impression that is particularly apparent in flight. A dark chestnut panel on the underwing-coverts may be particularly obvious if a bird is flushed or seen overhead. The long yellow bill and yellow legs add to the more colourful impression in flight (most obvious on adults in full breeding condition). When flying head-on, it shows deep buff ‘landing lights’ at the bend of the wing (white on Grey Heron). Juvenile Distinctive in its own right, being strikingly sandy-brown over the neck and upperparts, lacking the adult’s prominent black neck-stripes and its dark chestnut and purple areas. Closer views reveal broad buff feather fringes to the upperparts, narrow broken stripes on the foreneck and a faint shadow of the adult’s facial pattern. Juvenile Purple Heron is so brown that it may suggest a Bittern Botaurus stellaris, but it has a typically heron-like shape, with the prominently bulging neck, long bill, large feet and black primaries and secondaries. Bittern looks much more ‘owl-like’ in flight. First-summer Juvenile plumage is retained until the birds arrive in Africa where a partial moult takes place in their first winter, involving the body and some wing-coverts. It seems that at least some immatures remain there during their first summer (Cramp & Simmons 1977). Those that return north are adult-like but retain variable amounts of buff feathering, particularly across the upperwing-coverts (obvious in flight). Some are more juvenile-like, the neck stripes being browner and less well developed; others show only a ‘ghost’ of the adult’s face stripe and lack the distinctive black stripe on the side of the neck. They may retain at least some old juvenile secondaries, which appear contrastingly browner and also slightly shorter than the new black feathers. Older immatures From the autumn of their second calendar year, young Purple Herons become much more adult-like, although it seems that second-summers may still retain signs of immaturity, such as brown feathering in the crown, duller plumage and the retention of some broad pale feather fringing on the wing-coverts (Cramp & Simmons 1977). Unfortunately, these immature plumages do not appear to have been well studied and there is also likely to be significant individual variation.
Call Higher-pitched, shorter, quieter and gruffer than Grey’s.
Melanistic Grey Heron Dark Grey Herons (melanistic or stained) are not infrequent. Their identification should be relatively straightforward, particularly if careful attention is paid to the structural and plumage differences outlined above (but beware of distant birds or those seen briefly).
Reference Cramp & Simmons (1977).
Where and when Little, Great White and Cattle Egrets were formerly vagrants to Britain. Little Egret first bred in 1996 and, by 2010, the breeding population was approaching 1,000 pairs, with at least 4,500 wintering. It is commonest in England and Wales, but is scarce in Scotland. Great White Egret remains rare, but is increasing, with breeding in Somerset from 2012. Cattle Egrets have also increased, with as many as 168 recorded in 2008, and a pair bred in Somerset in 2008–09. Since then, numbers have declined due to a series of cold winters. It remains to be seen whether the species will eventually colonise.
By far the commonest egret, occurring in a wide variety of wetland habitats, both fresh and saline. It feeds in shallow water, either by stalking or energetically chasing mobile prey. Like Cattle Egret, it will also feed on earthworms in damp fields, sometimes associating with cattle. It nests in trees, often with Grey Herons Ardea cinerea.
Structure Medium-sized, slim and elegant; about two-thirds the size of Great White Egret. Long, thin neck and a long, slim, dagger-like bill. Longish black legs project well beyond the tail in flight, with the adults’ bright yellow feet being both obvious and diagnostic (grey-green on juveniles). It fails to show an obvious neck pouch in flight (appearing rather ‘flat-necked’ compared to Great White). Its flight is rather flappy and energetic (cf. Great White).
Plumage Adult In late winter, spring and summer two long plumes hang down the nape and it also has full plumes on the lower breast, back and scapulars, the latter forming a ‘fluffy train’ that overhangs the tail. To all intents and purposes, it loses the plumes in autumn (maybe just a vestige on the nape, back and scapulars and a slight ruff on the breast). Juvenile Weaker and fluffier looking plumage than the adult, often appearing distinctly ‘textured’ on the breast. It lacks long plumes but, when the head feathers are raised, it often shows a slight tufted effect to the fore-crown and a ragged impression at the rear, with an inconspicuous short plume often visible, and also a slight ruff on the breast (young birds may also retain traces of down on the head). Post juvenile moult takes place from August to November (BWP).
Bare parts Adult The bill is black, sometimes with grey or pink along the base of the lower mandible. The bare lores vary from dull blue-grey to lime green and dull yellow, but for a short period in spring, when in full breeding condition, both the bill and legs become intensely black and the lores a vivid purplish-pink, with deep blue nearer the eye. Juvenile Easiest to age by foot colour: grey-green or greyish-yellow. Initially, the legs are also green, gradually turning black, but with variable amounts of grey-green extending up the legs to the ‘knees’ and thighs. Initially, the bill has a dark tip contrasting with an extensive pinkish base, but it gradually darkens, becoming a rather messy pale grey and then black, often with pink retained along the basal two-thirds of the lower mandible. The lores are an insipid grey, blue-grey, lime green or even pinkish.
Call A distinctive, deep, guttural arggh arggh, sometimes more of a blood-curdling, drawn-out rasping kaaaaa.
Structure, posture and feeding action A very large egret, similar in size to Grey Heron (may be even taller in direct comparison). It is about one-third as big again as Little Egret and, when seen together, Great White towers over its smaller relation. Despite this size difference, it is surprisingly easy to confuse with Little Egret, especially at a distance and/or when direct size comparisons are not possible. Particular caution should be exercised with distant birds in flight. It has a long, slim, dagger-like bill and long legs but the most obvious structural feature is the remarkably long, thin snake-like neck. When feeding, it is often held in a distinctive shape, with the upper neck curved but the lower neck straight (like a question mark or the metal hook of a coat hanger). Also when feeding, it often stretches its neck out sideways at a bizarre angle, c. 45 degrees to the body, creating a very distinctive posture as it searches for food. It is a slower, more methodical and less energetic feeder than Little Egret (more like Grey Heron) and it does not ‘gallop’ after prey like the smaller species. Despite its large size and pure white plumage, it is surprisingly adept at disappearing into waterside vegetation.
In flight Appears very large (similar in size to Grey Heron) with a similar slow, easy flight action, but with shallower wingbeats and less bowed wings (back-on, it could be mistaken for a Mute Swan Cygnus olor, which is unlikely with Little Egret). Its wings are slightly but distinctly narrower, less rounded and more tapered than Grey Heron’s, most obvious in direct comparison. It tends to glide and soar more than Little Egret. Its long, pointed bill and strikingly long legs are obvious and it also shows an obviously rounded neck pouch, reminiscent of Purple Heron Ardea purpurea (flatter on Little Egret).
Plumage Adult In summer, it lacks Little Egret’s plumes on the rear head but has long fluffy ones on the scapulars, which often hang down over the tail (often in strands when wet, but sometimes stuck together in a single long, thin strand). The bill is deep black, with contrasting blue-grey or lime-green lores, and the legs are also black (including the feet) but with yellow on the tibia, down to and including the ‘knees’. For a short period when in full breeding condition, the bill becomes an intense black, the base of the lower mandible and the lores a vivid turquoise-green and the legs pale red (this odd combination of colours creating an extremely attractive appearance). By late summer, orange or bright primrose-yellow starts to appear on the bill base, gradually increasing in size so that, by autumn, the bill is completely orangey-yellow, remaining this colour throughout the winter. Unlike Little Egret, the gape line extends a short distance back below and beyond the eye. Juvenile Similar to winter adult, with bright orangey-yellow bill, lime-green lores and black legs with dull yellow above the ‘knees’ (variable in extent).
Cattle Egret is a bird of grasslands, where it hunts for insects and other prey around the feet of grazing herbivores (but Little Egret may also feed in this way). It has adapted this behaviour to take advantage of the spread of pastoral farming and is now one of the world’s most successful birds.
Structure Although about the same size as Little Egret (slightly smaller) it has a shorter, thicker bill, a shorter neck, a stockier body and shorter legs. It also has a distinctive ‘jowl’ (the feathering of the chin extending below the base of the lower mandible) and a rather ragged forecrown.
In flight More compact than Little Egret, with slightly shorter wings and shorter all-dark legs and feet. It should be noted, however, that flying Cattle Egrets can be surprisingly difficult to distinguish from Little, even in mixed flocks.
Plumage Adult In breeding plumage, easily identified by its pale orange crown, breast and lower back. It lacks Little Egret’s long head plumes, but has a short mane of longer feathering on the nape and also longer buff plumes on the mantle, hanging down over the tail.
The most obvious difference, however, is the relatively short, thick, pale orange or yellow bill, which is visible at some distance, even in flight. In full breeding condition, the bill briefly becomes red with a yellow tip, the lores an intense purple, the eye turns from yellow to deep red and the legs become deep pink (although initially they may be yellow). Non-breeding plumage is completely white. Juvenile Also completely white, but easily aged by its black bill (with pale yellow lores). As a consequence of its bill colour, the juvenile is much more likely to be passed off as a Little Egret. However, the bill gradually starts to turn yellow from about August onwards.
Coromandus Cattle Egret The race coromandus occurs in s. Asia, from Pakistan east to Australia. This form is kept in captivity and examples have escaped. It differs from the nominate in being perceptibly longer-billed and longer-necked but most distinctive is that, in summer plumage, it has more extensive orange on the head, neck and breast (with a white forehead and supercilium, and white down the centre of the throat, ending in a point on the upper breast, within the orange). It also shows paler orange on the back (with orange plumes). A pale buff wash to the forehead, crown, sides of the neck and breast may persist throughout the winter. One escaped bird in Somerset was in wing moult in mid February.
Squacco Heron Ardeola ralloides Although distinctly different from Cattle Egret, distant Squacco Herons are confusable in flight, particularly if seen below eye level, when the orange or buff ‘saddle’ (back and scapulars) may not be visible.
