Residential range of the berylline hummingbird. (Adapted from Howell and Webb, 1995)
None in English use; Chupaflor de berilo, Chupaflor colicanelo (Spanish).
Breeds in Mexico from southeastern Sonora and southern Chihuahua east to Veracruz and south through most of Mexico to western Honduras and El Salvador (Friedmann et al., 1950). Accidental in Arizona (Animas and Chiricahua Mountains).
A. b. viola (W. de W. Miller). Resident in the Sierra Madre Occidental from southeastern Sonora to Guerrero and east to eastern Michoacan.
Of A. b. viola: Wing, males 52–57.5 mm (ave. of 14, 55.5 mm), females 50.5–55.5 mm (ave. of 10, 53.9 mm). Culmen, males 18–20.5 mm (ave. of 14, 19.1 mm), females 19–21 mm (ave. of 10, 20 mm) (Ridgway, 1911). Eggs, 13.5–13.7 × 8.5–8.8 mm (Rowley, 1966).
The average of 13 males was 4.87 g (range 4.4–5.7 g); that of 8 females was 4.37 g (range 4.0–4.8 g) (Delaware Museum of Natural History).
Adult male. Above bright metallic green or bronze-green, passing into duller purplish bronzy on rump, the upper tail-coverts rather violet to violet-purple; middle rectrices metallic purplish, violet, to bronzy purple; the remaining rectrices chestnut, tipped, or broadly margined at tip, with purplish bronze (this sometimes wanting or obsolete on outermost rectrix); secondaries chestnut, or dull rufous-chestnut, broadly tipped with dusky, the innermost ones (tertials) mostly of the latter color; primaries chestnut or dull rufous-chestnut, with terminal portion extensively dusky, faintly glossed with purplish; malar region, chin, throat, sides of neck, chest, breast, sides, flanks, and upper abdomen bright metallic green (brighter and more yellowish than grass green), the feathers of chin and throat abruptly grayish white, those of underparts of body dusky brownish gray, beneath surface; lower abdomen pale buffy gray, grayish cinnamon, or isabella color; femoral and lumbar tufts white; under tail-coverts pale chestnut broadly edged basally and (usually) narrowly margined terminally with white; maxilla dull black; mandible reddish basally, dusky at tip; iris dark brown; feet grayish brown or dusky.
Residential range of the berylline hummingbird. (Adapted from Howell and Webb, 1995)
Adult female. Similar to the adult male, but slightly duller in color, especially the underparts; nearly the whole abdomen being dull cinnamon-buffy; the feathers of chin and throat showing more or less the basal or subterminal white.
In the hand. Differs from the two similar Amazilia species in that the bill is not strongly broadened at the base. Further, the green flanks and underparts set it apart from the other species, although in females these areas are duller and more brownish.
In the field. Associated with forest edges, banana groves, and coffee plantations in Mexico; in drier areas, associated with wooded streams. Although similar to the rufous-tailed and buff-bellied hummingbirds, these two species never have bright green underparts. Males are also more chestnut-colored on the rump, and especially on the upper wing surface. Only the lower mandible is reddish, compared with reddish upper and lower mandible color basally in the other two species. Females are duller and more like these in that the lower abdomen is grayish or brownish, but generally are somewhat brighter below than either of the two other species. The male’s call is a surprisingly loud bob-o-leek!, audible for some distance (Ruth Green, personal communication).
In Mexico the berylline hummingbird is common and widespread among the wooded highlands between 900 and 3000 meters, especially in rather dense pine, oak, or pine-oak woodlands, fir forests, open areas having scattered trees or shrubs, and suburban gardens or vacant lots (Edwards, 1973). It is abundant in Colima, and its ecological range includes the thorn forest, parts of the tropical deciduous forest, oak woodlands, and both arid and humid pine-oak forests (Schaldach, 1963).
Except at the northern edge of its range, this species is probably essentially a permanent resident, subject only to seasonal altitudinal movements. However, in Sonora it is evidently only a summer visitor in the oak-pine zone of the southeastern mountains at about 1500 meters (van Rossem, 1945).
The U.S. records of this species are nearly all for Arizona from June 20 to the end of September. The first sighting was in Ramsey Canyon in the Huachuca Mountains, when an individual was seen from late June to early August 1967 (Audubon Field Notes 21:593). In 1971 a female was observed in Cave Creek Canyon of the Chiricahua Mountains from June 30 to August 1 (American Birds 25:890), and in 1975 a berylline was observed from June 27 onward through the summer in Ramsey Canyon. Finally, on July 13, 1976, a pair was discovered nesting there, and at least one young had hatched by July 22; however, the nest was found abandoned on August 16. The species was again found nesting in Ramsey Canyon the following year (Anderson and Monson, 1981). Finally, in 1979 the species was seen in Carr Canyon, adjacent to Ramsey Canyon, for the only Arizona record that year (Continental Birds 1:108). Since then, more than 30 records for Arizona have accrued (American Birds 48:972), and there also have been records for New Mexico’s Guadeloupe Canyon and Big Bend National Park, Texas.
According to Des Granges (1979), the berylline hummingbird is a wandering but not migratory species that defends feeding territories. In his study area, Des Granges noted that it was a relatively generalist type of forager. During the summer months the social dominance of the amethyst-throated hummingbird prevented it from foraging at the best tubular flower (Malvaviscus arboreus) in the arid pine-oak habitat, so the berylline fed at Calliandra anomala instead. During the winter months, however, the amethyst-throated hummingbird became less common, allowing the berylline access to the Malvaviscus. In the riparian gallery forest habitat the birds also fed on tubular flowers such as Psittacanthus calyculatus, whereas in the arid thorn forest they were attracted to Ceiba aesculifolia and Lemairocereus.
Very few observations on the breeding of this species have been published. Rowley (1966) located nine nests in Oaxaca between July and October, five of them during September. An apparently favorite nesting site there is the shrub Wigandia caracasana. Its outer dead seed stalks offer ideal nesting sites, especially where the plant’s large leaves provide overhead protection from heavy rains. However, other nests were found in different flowering shrubs, one almost 5 meters up in an oak and another at least 15 meters above ground on the horizontal branch of a pine.
All the nests were abundantly covered by lichens, producing a nearly solid pattern. With a single exception they also always had a “streamer” of grass blades attached to the bottom with spider webbing, resulting in a very distinctive appearance. One of the nests measured nearly 50 mm in outside diameter, with an inside cup diameter of slightly more than 26 mm; it was about 50 mm in depth, exclusive of the streamer.
The first U.S. nesting in Cave Creek Canyon was in a riparian habitat at 1634 meters elevation; the nest was on a slender branch of an Arizona sycamore (Plantanus wrightii), about 7.5 meters above the ground. The second nest was in a similar habitat, at 1722 meters’ elevation in Ramsey Canyon, again located about 5.5 meters above ground in an Arizona sycamore. Both nests were covered with green leaf-like lichens and measured about 40 × 50 mm, with a cavity depth of 15 mm. The Ramsey Canyon nest is believed to have hatched between August 10 and 13, and the two young fledged on August 20 and September 1, suggesting a fledging period of about 20 days (Anderson and Monson, 1981).
This species is obviously a close relative of the buff-bellied and rufous-tailed hummingbird, and also of such forms as the blue-tailed hummingbird. Land (1970) noted that a Guatemalan population of the last-named species seems to represent an intermediate form, and thus perhaps the two should be considered conspecific. No definite hybrids are known, but the form described as Amazilia ocai may represent one involving the berylline hummingbird and the red-billed azure-crown (Berlioz, 1932).
Not enough is known of its foraging ecology to comment on interspecific relationships of this species.