Black-capped Chickadee
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| Poecile atricapilla (Linnaeus, 1766) |
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Parus atricapillus |
The Black-capped Chickadee, Poecile atricapilla, is a small songbird, a passerine bird in the tit family Paridae. Often, it is still placed in the genus Parus with most other tits, but mtDNA cytochrome b sequence data and morphology suggest that separating Poecile more adequately expresses these birds' relationships (Gill et al., 2005). The American Ornithologists' Union has been treating Poecile as distinct genus for some time already.
Adults have a black cap and bib with white sides to the face. Their underparts are white with rusty brown on the flanks; their back is grey. They have a short dark bill, short wings and a long tail.
Their breeding habitat is mixed or deciduous woods in Canada, Alaska and the northern United States. They nest in a hole in a tree; the pair excavates the nest, using a natural cavity or sometimes an old woodpecker nest. They may interbreed with Carolina Chickadees or Mountain Chickadees where their ranges overlap. The Black-capped and Carolina chicadees are virtually impossible to tell apart visually, but they are readily distinguished by call. Their point of overlap is near New Brunswick, New Jersey.
They are permanent residents, but sometimes move south within their range in winter. On cold winter nights, these birds reduce their body temperature by up to 10-12 °C to conserve energy.
These birds hop along tree branches searching for food, sometimes hanging upside down or hovering; they may make short flights to catch insects in the air. Insects form a large part of their diet, especially in summer; seeds and berries become important in winter. They sometimes hammer seeds on a tree or shrub to open them; they also will store seeds for later use. Black-capped Chickadees are known to remember the position of hundreds or more of their food caches for up to a month[citation needed].
During the fall migration and winter, chickadees often flock together. Many other species of birds, including titmice, nuthatches, and warblers can often be found foraging in these flocks. Mixed flocks stay together because the chickadees call out whenever they find a good source of food. This calling out forms cohesion for the group, allowing the other birds to find food more efficiently. When flocking, Black-capped Chickadees soon establish a rigid social hierarchy.
[edit] Calls
The vocalizations of Black-capped chickadees are highly complex (Ficken et al., 1978). 13 distinct types of vocalizations have been classified, many of which are complex and can communicate different types of information. Chickadees' complex vocalizations are likely an evolutionary adaptation to their habitat: they live and feed in dense vegetation, and even when the flock is close together, individual birds tend to be out of each others' visual range.
The song of the Black-capped is a simple, clear whistle of two notes, identical in rhythm, the first roughly a whole-step below the second. This is distinguished from the Carolina chickadee's four-note call fee-bee fee-bay; the lower notes are nearly identical but the higher fee notes are omitted, making the Black-capped song like bee bay.
The males only sing the song when in relative isolation from other chickadees (including their mates). In late summer, some young birds will sing only a single note. Both sexes sometimes make a faint version of the song, and this appears to be used when feeding young.
The most familiar call is the familiar chick-a-dee-dee-dee which gave this bird its name. This simple-sounding call is astonishingly complex. It has been observed to consist of up to four distinct units which can be arranged in different patterns to communicate information about threats from predators and coordination of group movement. Recent study of the call shows that the number of dees indicates the level of threat from nearby predators. An analysis of over 5,000 alarm calls from chickadees, it was found that alarm calls by triggered small, dangerous raptors had a shorter interval between chick and dee and tended to have extra dees, usually averaging four instead of two. In one case, a warning call about a pygmy owl, a prime threat to chickadees, contained 23 dees (Templeton et al., 2005). The Carolina Chickadee makes a similar call which is faster and higher-pitched.
There are a number of other calls and sounds that these Chickadees make, such as a gargle noise which is usually used by males to indicate a threat of attacking another male, often when feeding. This call is also used in sexual contexts. This noise is among the most complex of the calls, containing 2-9 of 14 distinct notes in one population that was studied.
[edit] Chickadees in Culture
- This is the provincial bird of New Brunswick and the state bird of Maine and Massachusetts.
- A Canadian children's magazine also goes by the name Chickadee.
[edit] References
- BirdLife International (2004). Parus atricapillus. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006. Database entry includes justification for why this species is of least concern
- Ficken, M.S.; Ficken, R. W. & Witkin S. R. (1978): Vocal repertoire of the Black-capped Chickadee. Auk 95(1): 34-48. PDF fulltext
- Gill, Frank B.; Slikas, Beth & Sheldon, Frederick H. (2005): Phylogeny of titmice (Paridae): II. Species relationships based on sequences of the mitochondrial cytochrome-b gene. Auk 122: 121-143. DOI: 10.1642/0004-8038(2005)122[0121:POTPIS]2.0.CO;2 HTML abstract
- Smith, Susan M. (1991): The black-capped Chickadee: Behavioural Ecology and Natural History. Cornell University Press. ISBN 0801423821 (1991 reprint)
- Templeton, C. N.; Greene, E. & Davis, K. (2005): Allometry of alarm calls: black-capped chickadees encode information about predator size. Science 308(5730): 1934-1937. PMID 15976305 DOI:10.1126/science.1108841 (HTML abstract)
[edit] External links
- Internet Bird Collection: Black-capped Chickadee videos. Retrieved 2006-NOV-21.
- BirdHouses101.com: Black-capped Chickadee. Retrieved 2006-NOV-21.
