The Mountain Chickadee is most similar to the Black-capped Chickadee, and overlaps with that species throughout its entire range in the province. The prominent white supercilium of the Mountain Chickadee should serve, under most conditions, to easily distinguish between the two species. In very worn or faded individuals, however, this characteristic may be reduced and much less distinctive. Fortunately, the extensive buffy wash on the sides and flanks of Black-capped Chickadee, as well as the white edges of the greater wing coverts and secondaries of that species, allow for additional separation from Mountain Chickadee (which has a pale greyish wash on the sides and flanks and lacks pale feather edges on the uniformly grey wings). The other two species of chickadee in British Columbia, Chestnut-backed Chickadee and Boreal Chickadee, are extensively brownish or chestnut and are easily distinguished from Mountain Chickadee under even marginal conditions.
| Vocal repertoire, as in most chickadee species, is relatively complex. The most commonly-heard call year-round is a classic chick-a-dzee-dzee that is distinctly rough, burry, and hoarse. It is slower and much burrier than the analagous call of the Black-capped Chickadee, but slightly quicker and not as wheezy or nasal as the call of Boreal Chickadee. The song is a series of 3-6 (usually 3-4) high, clear whistles, often with the pattern fee-beee-bayyy or fee-beee, fee-bayyy; the song may include individial notes on different pitches (usually descending) or may be all on one pitch. This song is similar to that of the Black-capped Chickadee, but in that species the song is consistently 2-parted and descending. When foraging, individuals constantly produce a variety of soft, thin contact calls, occasionally giving more complex, warbling, gargled tsiddleeuu notes. A wide variety of additional calls are also given by this species, but these are typically only in highly specific situations. Source: Harrap and Quinn (1995); McCallum et al. (1999); Sibley (2000); Hess (2006) |
Courtship
This species mates monogamously, with pairs typically lasting throughout the life of the birds involved. Pre-copulatory behaviour commonly involves the feeding or presenting of food by the male to the female.
Nest
Nest selection occurs as early as early to mid-April, rarely more than a week before the eggs are laid. The Mountain Chickadee is a typically a secondary cavity nester, utilizing already-existing cavities (either naturally-occurring or resulting from excavation by woodpeckers and other primary cavity nesters) in snags or dead trees in which to place the nest. Some individuals apparently partially excavate their own nests, but this remains unconfirmed and may not be a common practice. The size, shape, and orientation of the cavity is highly variable and is more reflective of natural variation in cavities rather than the preference of the birds. Cavities in both coniferous and deciduous trees are selected, although there may be a slight preference for deciduous trees when they are available. It has rarely been recorded nesting on the ground in old rodent burrows or rock crevices. Nest height ranges from 20 cm to over 18 m, with most nests occurring between 1 and 5 m in height. The floor of the cavity is lined with a well-packed, circular base of wood chips, lichen, moss, feathers, and grass and topped with loose fur or hair, pieces of owl pellets, and other materials. A distinct cup is molded into this base of material in which to lay the eggs. This species commonly uses nest boxes, and may even prefer these over natural cavities when they are present.
Eggs
A clutch of (5) 6-9 (12) eggs is laid between mid-April and mid-June, with most clutches laid between mid-May and early June. This species is possibly double-brooded, as evidenced by observations of eggs between late June and mid-July. The smooth, non-glossy eggs are pure white, sometimes with very fine reddish-brown or light red speckling (commonly forming a wreath around the larger end), and are incubated solely by the female over a period of 13-14 days. This species is a very rare host for Brown-headed Cowbird parasitism, with only a single occurrence from Colorado being reported. Eggs are present in B.C. between mid-April and late July.
Young
The young are fully altricial upon hatching and are largely naked except for a few tufts of natal down. The nestlings are tended (both feeding and brooding) by both parents during their time in the nest, although the female broods the young for much longer periods of time than the male. The young fledge at 14-23 days of age, after which they remain with the parents for 2-3 weeks before dispersing and becoming independent. Nestlings and dependent fledglings are present in B.C. between early May and mid-August.
Source: Harrap and Quinn (1995); Baicich and Harrison (1997); Campbell et al. (1997); McCallum et al. (1999)
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This species feeds primarily on small insects and spiders during the breeding season and on conifer seeds at other times of the year. During the summer, it gleans moth larvae, sawfly larvae, beetles, aphids, scale insects, and spiders from the foliage, cones, and bark of coniferous trees, foraging at all levels from near the ground well into the canopy. It is an active forager and commonly hangs upside down by its feet while gleaning prey from the underside of branches or boughs or probes needle clusters at the tips of branches. Foraging birds occur singly or in pairs during the breeding season, but form larger flocks of up to 20 or more individuals at other times of the year; flocks commonly associate with other species such as nuthatches, creepers, and kinglets, usually forming the nucleus of these mixed-species feeding flocks. During the fall and winter, when insect abundance declines significantly, the Mountain Chickadee switches to a diet that is composed primarily of the seeds of coniferous trees, especially Lodgepole Pine, Ponderosa Pine, Douglas-fir, and spruce; however, during the winter it also consumes berries and sometimes opens galls in conifer needles and twigs to gain access to insect larvae that are contained within. It commonly caches seeds during the winter and slowly consumes them over an extended period of time. This species is a common visitor to bird feeding stations, where it prefers sunflower seeds.
Source: Harrap and Quinn (1995); McCallum et al. (1999)
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