The Chimney Swift is a small bird (a type of swift).
In flight, this bird looks like a flying cigar with long slender curved wings. The plumage is a sooty grey-brown; the throat, breast, underwings and rump are paler. They have short tails. Chimney swifts also have the shortest legs of any bird native to Ontario.
The breeding season of Chimney Swifts is from May through July. Their breeding habitat is near towns and cities across eastern North America. Originally, these birds nested in large hollow trees, but now they mainly nest in man-made structures such as large open chimneys. The nest is made of twigs glued together with saliva and placed in a shaded location. They will lay three to seven white eggs, which the female will cover at night. The incubation period is 19-20 days, and the fledglings leave the nest after a month. Chimney swifts can nest more than once in a season. While Chimney swifts will roost together in large numbers, it is rare to find more than one nest per chimney. Nesting sites are normally small chimneys but nests are also built in large communal roosts. It is suspected that fledged young are often fed by their parents while the young roost together in large communal roosts.