12/24/2023 0 Comments Crows chimney sweep![]() ![]() The sexes are identical in plumage, though males average slightly heavier than females. This is a medium-sized swift, measuring from 12 to 15 cm (4.7 to 5.9 in) in length, with a wingspan of 27 to 30 cm (11 to 12 in) and a weight ranging from 17 to 30 g (0.60 to 1.06 oz). Its common name refers to its preferred nesting site and its speedy flight. This is thought to be a reference to its nomadic lifestyle rather than to any reference to the sea, a theory strengthened by the later assignment of the specific name pelasgia (after the nomadic Pelasgi tribe of ancient Greece) to the same species by other ornithologists. The specific name pelagica is derived from the Greek word pelagikos, which means "of the sea". ![]() This is an apt description of the bird's tail, as the shafts of all ten tail feathers ( rectrices) end in sharp, protruding points. The chimney swift's genus name, Chaetura, is a combination of two Ancient Greek words: chaite, which means "bristle" or "spine", and oura which means "tail". It is also closely related to the Chapman's swift in the past, the three were sometimes treated as a single species. Separated for millennia by vast ice sheets, the survivors evolved into two species which are still separated by a wide gap across the continent's midsection. Scientists believe that the two species evolved from a common ancestor that was forced to North America's southeastern and southwestern corners by glacial advances. The chimney swift's closest relative is Vaux's swift. In 1825, James Francis Stephens moved this and other small, short-tailed New World swifts to the genus Chaetura, where it has since remained, although some authorities in the 1800s assigned it to a variety of now obsolete genera. This misconception continued well into the 1800s, with ornithologists calling it "American Swallow" (e.g. When Carl Linnaeus first described the chimney swift in 1758, he named it Hirundo pelagica, believing it to be a swallow. The average chimney swift lives 4.6 years. The altricial young hatch after 19 days and fledge a month later. It builds a bracket nest of twigs and saliva stuck to a vertical surface, which is almost always a human-built structure, typically a chimney. The chimney swift feeds primarily on flying insects, but also on airborne spiders. ![]() Like all swifts, it is incapable of perching, and can only cling vertically to surfaces. The chimney swift is a medium-sized, sooty gray bird with very long, slender wings and very short legs. A member of the genus Chaetura, it is closely related to both Vaux's swift and Chapman's swift in the past, the three were sometimes considered to be conspecific. The chimney swift ( Chaetura pelagica) is a bird belonging to the swift family Apodidae. ![]()
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