Black-tailed Gnatcatcher
Polioptila melanura
Passeriforme Order – Polioptilidae Family
BIOMETRICS:
L : 10-11 cm
Poids : 5 g
DESCRIPTION:
Black-tailed Gnatcatcher is a small, long-tailed songbird.
Adult male in breeding plumage has blue grey upperparts. Crown is glossy black, with white eye ring. Flight feathers are dark brown with whitish edges. Tail is black. Outer tail feathers show white outer webs, and broad white tips, but closed tail appears rather black below.
Underparts are whitish, with buff wash on flanks. Chin and throat are white.
Thin, pointed bill is black. Eyes are dark brown. Legs and feet are blackish.
Adult female in breeding plumage resembles male in basic plumage. She has pale lores and indistinct eye ring. Any black on face. She has brownish greater wing coverts, back and rump.
Both sexes in basic plumage have paler upperparts. Male has grey head, but we can see a black stripe over the eye.
During winter, birds may perform territorial behaviour, but they are also seen in loose flocks, or wandering in pairs after breeding season.
Pairs are monogamous. Male calls before copulation, pursues female through dense vegetation with fluffed up feathers. Female responds with soft calls.
Against the predators, Black-tailed Gnatcatcher performs chasing, and particularly against the Brown-headed Cowbird which is frequently attacked.
FLIGHT:
Black-tailed Gnatcatcher has an undulating flight, with short wing beats bursts over very short distances, about 2 to 3 metres. It is not a strong flier.
REPRODUCTION:
Black-tailed Gnatcatcher’s nest is built by both sexes, but mainly by female. It is situated in fork, shaded and shielded on all sides, under canopy or large branch. Nest is often in dense, thorny or leafy shrub or tree, from 60cm to 5 metres above the ground. Birds may reuse old nest, repairing and relining it. New nests in the same season will include old nests’ materials.
Nest is a deep, compact cup. Outer part is made with woven plant fibres, but lacks external lichens covering. Interior is lined with plant down, feathers, fur, cotton and silky down. Male may carry some material in bill, and offer it to female.
Female lays 3 to 5 very pale coloured eggs, marked with darker colours. Incubation lasts about two weeks, shared by both parents. Chicks are fed by both adults approaching while uttering soft “tsh” before landing at nest with food. Young fledge about 9 to 15 days after hatching. Parents stop to feed them within three weeks after fledging.
This species produces two broods per season.
DIET:
Black-tailed Gnatcatcher feeds mainly on insects, rarely on seeds and fruits.
PROTECTION / THREATS / STATUS:
Black-tailed Gnatcatcher needs native vegetation at ground level, and can’t adapt to exotic plants or intensive urbanization. They may abandon nest if disturbed by humans. However, populations seem to be stable at this moment.
Fr : Gobemoucheron à queue noire
All : Schwarzschwanz-Mückenfänger
Esp : Perlita de Cola Negra
Ital : Zanzariere codanera
Nd : Zwartstaart-muggenvanger
Sd : Svartstjärtad myggsnappare
Photograph by Tom Grey
His website :
Tom Grey's Bird Pictures
Photograph by Pete Moulton
His website : Pete Moulton Photography
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD Vol 11 by Josep del Hoyo, Andrew Elliott and David Christie - Lynx Edicions - ISBN: 849655306X
A GUIDE TO THE BIRDS OF MEXICO AND NORTHERN CENTRAL AMERICA by Steve N. G. Howell, Sophie Webb - Oxford University Press - ISBN: 0198540124
FIELD GUIDE TO THE BIRDS OF NORTH AMERICA by National Geographic Society - National Geographic Society - ISBN: 0792274512
What Bird-The ultimate Bird Guide (Mitchell Waite)
Similar species: California Gnatcatcher is darker below, with undertail feathers more extensively black with narrow white tips to outer rectrices. Eye ring is indistinct.
VOICE: SOUNDS BY XENO-CANTO
Black-tailed Gnatcatcher’s call is a loud, nasal, slightly buzzy “jehrr”, often repeated twice. We can also hear a thin “jiihh”, a sharp “chip-chip-chip”, and a low, rasping “ssheh-ssheh”. Song is a rapid series of nasal “jeh-jeh…”
HABITAT:
Black-tailed Gnatcatcher lives in arid to semi-arid areas, desert scrub, open and semi-open areas with scattered bushes and scrubs, riparian brushy woodlands.
Winter range is the same kind of habitat. Black-tailed Gnatcatcher may be found in areas with evergreen and semi-deciduous vegetation.
RANGE:
Black-tailed Gnatcatcher ranges throughout Sonora Desert of SW United States and northern Mexico. This species doesn’t migrate and may be found in arid areas year-round.
BEHAVIOUR:
Black-tailed Gnatcatcher searches for insects through trees and bushes, by gleaning, hawking and hovering. Insects are gleaned from lower branches of shrubs. It also hovers to pick preys from foliage. While searching for food, it hops from perch to perch, scolding, very active, and always moving. It may flick tail from side to side when searching. It rarely catches insects on the wing. It prefers to alight in open shrubs and forage, cocking head from side to side, and then looking up and down. These birds forage in pairs. Bird carries prey to nearby cover, kills it by trashing against a branch, and gives numerous stabs along the body to soften it, before to swallow it whole.
During breeding season, males may be aggressive to each other before and after courtship displays. Male may fly towards intruder, giving harsh “tsh” calls, but usually avoids physical contact by abruptly veer off. Both sexes attempt to chase away from nest-site the larger birds.
Pair probably remains together all year-round, defending territory. In order to establish and maintain its territory, male calls from exposed perch, flies from perch to perch, calling several times from each place. Male maintains its territory by flying within boundaries over its territory.
