Adult male The plumage is overall dull greyish, paler on the throat and underparts, with a brownish wash on the crown, nape, auriculars, and sides of the neck and a buffy wash on the sides and flanks. The upperparts, wings, and long, slender tail are relatively pure grey. The iris is dark, the short, pointed bill is blackish, and the legs and feet are blackish.
Adult female The plumage of the female is identical to that of the male, but females can be distinguished from males by their yellow or whitish (vs. dark) iris.
Juvenile Juveniles resemble adults in plumage pattern, although very young females have a dark iris like adult males (the iris becomes pale within several weeks).
Measurements Total Length: 10-11 cm Mass: 4.5-6.0 g
The behaviour, vocalizations, size, and plumage of this species are all distinctive, and it is unlikely to be confused with any other species in British Columbia.
Foraging flocks, as well as pairs and single individuals, give a nearly continuous chatter of soft, often burry twitterings that incorporate a wide variety of notes, including sharp, scraping skrrti ti ti calls, dry spik notes, and high, thin, scraping tseeez tzee tzee tzee calls given in a long, slightly descending series. Flocks give a loud, high, clear , descending tsididididididi or sre-e-e-e-e-e-e-e when an aerial predator (owl, hawk) flies overhead.
Courtship Pair bonds are often maintained for more than one year, with new pairs being formed in late winter (late January or February). During courtship, the male chases and pursue the female while uttering soft contact calls, subsequently pecking the female near the cloaca to stimulate copulation.
Nest Nest construction begins early in the year, with some nests being initiated as early as February; most nests are built during March and April. Both sexes contribute to the construction of the nest, which occurs over a period of 2-5 weeks. The nest is a distinctive, pendulous, gourd-shaped “sock” 20-25 cm in length with a small horizontal entrance hole near the top. Nests are placed in coniferous or (more commonly) deciduous trees and shrubs in brushy areas or along forest edges. The nest is typically attached at the top to several small twigs and hangs vertically; nest heights range from 0.6-15 m, with most nests occurring between 2-3.5 m above the ground. The nest consists of tightly, intricately woven strands of moss, lichens, twigs, leaves, cocoons, rootlets, spider webs, fine grasses, hair, and plant fibres. The interior of the nest is lined with finer materials, including plant down, hair, and feathers. Nests are often used for more than one season, and replacement nests are often created from the remains of nests that have been destroyed by weather or predation.
Eggs A single clutch of (4) 5-7 (8) smooth, slightly glossy, white eggs is laid between mid-March and mid-July, with most clutches initiated between mid-April and mid-May (later clutches include both replacement clutches as well as second [and even third] broods). More than one female may occasionally lay eggs in a single nest, as evidenced by clutches of up to 15 eggs in some nests. Both sexes incubate the eggs for a period of 12-13 days before hatching. This species is rarely parasitized by the Brown-headed Cowbird. Eggs occur in British Columbia between mid-March and late July.
Young The young are naked and fully altricial at hatching, with scant hair-like greyish-white down soon appearing. The nestlings are tended by both parents and remain in the nest for 14-18 days before fledging. Fledglings then remain associated with (and tended by) the parents for an additional 8-14 days before becoming fully independent. Nestlings and dependent fledglings occur in British Columbia between mid-April and mid-August, although most occur between early May and mid-June.
Source: Harrap and Quinn (1995); Baicich and Harrison (1997); Campbell et al. (1997); Sloane (2001)
The Bushtit forages in pairs or small to large (10-40+ individuals) flocks throughout the year, and is rarely encountered as single individuals. Although flocks sometimes associate with other small passerines (kinglets, chickadees, nuthatches), they tend to remain somewhat separate from these other species and are more commonly encountered as single-species groups. Bushtits feed on a wide variety of small insects and spiders, which are gleaned from leaves, twigs, and branches of brushy vegetation. A relatively small amount of vegetable material (seeds, berries, small galls) is also included in the diet, but typically comprises less than 20% of all foods taken. Flocks often visit feeding stations, especially in suburban environments, where they commonly swarm suet feeders en masse.
Source: Sloane (2001)
The Bushtit is characteristic of brushy habitats throughout its range. In B.C., it is found in shrubby hedgerows, seaside thickets, brushy estuaries, powerline rights-of-way, brushy parks, suburban gardens, open forests, Garry Oak woodlands, and forest edges. It readily occurs in and around human habitation, including desnsely populated urban and suburban areas wherever shrubby vegetation is present.
Source: Campbell et al. (1997)
Resident along the Pacific coast from southwest British Columbia to Baja California, as well as east through the western United States to Colorado, extreme western Oklahoma, and central Texas. It also occurs throughout much of interior Mexico, south to Chiapas and Guatemala.
Resident Fairly common to common on the southern coast, including the Lower Mainland (east to Chilliwack and Hope, north to Squamish), Gulf Islands, and southern and eastern Vancouver Island (north regularly to Campbell River and Sayward, and west to Sooke and Jordan River). Rare to uncommon farther north along the southern mainland coast (Sunshine Coast, Powell River) as well as on western Vancouver Island (including Tofino and Ucluelet). Small numbers may wander to higher elevations during late summer and early fall.
Vagrancy Casual during summer in the Whistler-Pemberton area, and casual throughout the year in the Okanagan Valley of the south-central interior, becoming accidental in summer farther north in the interior to the Shuswap Lake region.
Source: Campbell et al. (1997)
Population and Conservation Status
Prior to 1900, it appears that this species was only an irregular resident of the Lower Mainland. This species was not recorded outside of this area of the province prior to the 1930s, but by the 1940s it was noted as occurring regularly in small numbers on southern Vancouver Island. Provincial populations increased most dramatically during the 1970s, and the species is now a common and characteristic species on much of the south coast. It adapts readily to disturbed and developed landscapes, and is not recognized as a species of conservation concern by either federal (COSEWIC [Committee on the Status of Endangered Wildlife in Canada]) or provincial (BC CDC [Conservation Data Centre]) bodies.
Source: Campbell et al. (1997)
Nine subspecies of Bushtit are currently recognized, which fall into three well-defined subspecies groups: the coastal “Common Bushtit” group (P.m.minimus grp.), the interior “Lead-coloured Bushtit” group (P.m.plumbeus grp.) of the western United States, and the “Black-eared Bushtit” group (P.m.melanotis grp.) of Mexico. Although these three subspecies groups are relatively well-defined (with the exception of some intergradation between the plumbeus and melanotis groups in the southwestern U.S.), subspecies within each group are rather weakly-defined. Only P.m.saturatus (Ridgway), the northernmost representative of the minimus group, occurs in British Columbia. The minimus group is distinguished from the plumbeus group by its brownish (vs. greyish) crown and nape and overall darker, browner, and dingier plumage.
The Bushtit is the only New World representative of the primarily Old World family Aegithalidae, which reaches its greatest diversity in the Himalayas and southeast Asia (where 6 of the 8 species are found).
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2017. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
17/08/2017 4:18:26 PM]
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