The Chestnut-backed chickadee or Poecile rufescens is a non-migratory, perching bird in the Paridae family.It is native to the coastal rainforests of the Pacific Northwest and western Canada, with its habitat extending to southern Alaska at the most northern point and southwestern California at its most southern. Urban and rural dwelling chickadees are common where trees and bushes are abundant (All About Birds 2017).
P. rufescens is the smallest chickadee, at 12 cm in length and weighing between 5.5 - 11.3 g (All About Birds 2017). While physically similar in size and color to the Black-capped chickadee, it is differentiated by the dark brown feathers on its head and the bright chestnut on its back, shoulders, and flanks that are its namesake (Audubon 2017). The cheek and nape, as well as the as edges of the wing coverts, are white, while off-white feathers cover the breast and belly. The tail and the greater part of the wings are grey.
P. rufescens has no true song, but communicates in chirps that vary in speed. Food (berries and conifer seeds) is obtained from the surfaces of branches and twigs as they hop, usually working their way up from the bottom of a tree to the top. Additional foraging methods include probing into the crevices of trees and launching out from a perch to catch flying prey such as insects and spiders. New nests are excavated in soft, rotting wood, but they also use abandoned woodpecker nests and man-made bird houses. The female uses moss, bark, lichen, found fibers and feathers to form the foundation of the nest and then finishes it with fur from animals like deer and coyotes. The average clutch size is 6 eggs, laid between April and May with infrequent broods in June and July. The eggs are usually white but some do have a reddish-brown tint at the larger end (Burke Museum 2017). When adults leave the nest to forage, the eggs are hidden under a thin layer of fur to protect them from predators. It is likely that both parents tend to the young, but for what amount of time is still unknown.
P. rufescens is active and very social. Where populations overlap, they live alongside other chickadees and travel in mixed flocks during the winter. They exhibit territorial behavior during the mating season in April and May (Audubon 2017). The population is currently stable and common in the dense, humid forests of its range, with some recent habitat expansion into drier areas. Nesting in rotting and dead cavities leaves chestnut-backed chickadees vulnerable to loss of habitat through forest management practices, clear-cutting and, to a lesser extent, human expansion (All About Birds 2017).
The chestnut-backed chickadee (Poecile rufescens), formerly Parus rufescens, is a small passerine bird in the tit family, Paridae.
It is found in the Pacific Northwest of the United States and western Canada, from southern Alaska to southwestern California. It is a permanent resident within its range, with some seasonal movements as feeding flocks move short distances in search of food. They usually move to lower elevations in the same area upon onset of winter and move back up to higher elevations in late summer.
Chickadees are able to use nocturnal hypothermia to regulate energy expenditure, allowing them to survive harsh winters where other bird species not utilizing thermal regulation would not be able to. Some estimates put the energy conserved while using nocturnal hypothermia all the way up to 32%.[2]
It is a small chickadee, 11.5–12.5 cm (4.5–4.9 in) long with a weight of 8.5–12.6 g (0.30–0.44 oz). The head is dark blackish-brown with white cheeks, the mantle is bright rufous-brown, the wing feathers are dark gray with paler fringes. The underparts are white to pale grayish-white, with rufous or pale gray flanks. It is often considered the most handsome of all chickadees.[3] They often move through the forest in mixed feeding flocks, and are often seen in large groups with bushtits and warblers.
There are three subspecies, with the flanks being grayer and less rufous further south:[4]
Its habitat is low elevation coniferous and mixed coniferous forests. In the San Francisco Bay Area this bird has readily adapted to suburban settings, prompting a range expansion. It is a cavity-nester, usually utilizing an abandoned woodpecker hole, but sometimes excavating on its own. Chestnut-backed chickadees use much fur and hair to make their nests. Their nests are actually 50% fur and hair. The most common hair they use comes from deer, rabbits, and coyotes. The adult chickadees also make a layer of fur about a centimeter thick which is used to cover the eggs on the nest whenever they leave the nest. It lays 5–8 (sometimes 9) eggs per clutch.
Its food is largely insects and other invertebrates gleaned from foliage. Chestnut-backed chickadees take some seeds, especially those of conifers, and fruit. It will visit bird feeders, including hummingbird feeders, and especially loves suet.
Molecular phylogenetic studies have shown that the chestnut-backed chickadee is sister to the boreal chickadee (Poecile hudsonicus).[5][6][7]
Del Valle, CA
Poecile rufescens rufescens
P. r. barlowi
The chestnut-backed chickadee (Poecile rufescens), formerly Parus rufescens, is a small passerine bird in the tit family, Paridae.
It is found in the Pacific Northwest of the United States and western Canada, from southern Alaska to southwestern California. It is a permanent resident within its range, with some seasonal movements as feeding flocks move short distances in search of food. They usually move to lower elevations in the same area upon onset of winter and move back up to higher elevations in late summer.
Chickadees are able to use nocturnal hypothermia to regulate energy expenditure, allowing them to survive harsh winters where other bird species not utilizing thermal regulation would not be able to. Some estimates put the energy conserved while using nocturnal hypothermia all the way up to 32%.
It is a small chickadee, 11.5–12.5 cm (4.5–4.9 in) long with a weight of 8.5–12.6 g (0.30–0.44 oz). The head is dark blackish-brown with white cheeks, the mantle is bright rufous-brown, the wing feathers are dark gray with paler fringes. The underparts are white to pale grayish-white, with rufous or pale gray flanks. It is often considered the most handsome of all chickadees. They often move through the forest in mixed feeding flocks, and are often seen in large groups with bushtits and warblers.
There are three subspecies, with the flanks being grayer and less rufous further south:
Poecile rufescens rufescens (Townsend, 1837). Alaska south to northwest California. Broad rufous band on flanks. Poecile rufescens neglectus (Ridgway, 1879). Coastal central California (Marin County). Narrow rufous band on flanks. Poecile rufescens barlowi (Grinnell, 1900). Coastal southwestern California (south of San Francisco Bay). Almost no rufous color on flanks.Its habitat is low elevation coniferous and mixed coniferous forests. In the San Francisco Bay Area this bird has readily adapted to suburban settings, prompting a range expansion. It is a cavity-nester, usually utilizing an abandoned woodpecker hole, but sometimes excavating on its own. Chestnut-backed chickadees use much fur and hair to make their nests. Their nests are actually 50% fur and hair. The most common hair they use comes from deer, rabbits, and coyotes. The adult chickadees also make a layer of fur about a centimeter thick which is used to cover the eggs on the nest whenever they leave the nest. It lays 5–8 (sometimes 9) eggs per clutch.
Its food is largely insects and other invertebrates gleaned from foliage. Chestnut-backed chickadees take some seeds, especially those of conifers, and fruit. It will visit bird feeders, including hummingbird feeders, and especially loves suet.
Molecular phylogenetic studies have shown that the chestnut-backed chickadee is sister to the boreal chickadee (Poecile hudsonicus).
