Distribution and Migration
As their name suggests, Chimney Swifts are primarily found in urban areas and frequently roost in chimneys. These birds are almost constantly on the wing – they eat, drink, and bath while in flight (bathing by gently skimming the surface of a body of water). They move erratically in flight, banking from side to side. In the rare moments when these birds perch during the day, they cling to vertical surfaces and use their stiff tail to press against the perching surface for support.
The breeding range of the Chimney Swift extends across the eastern and central US, and the southern part of eastern and central Canada (Nova Scotia to Saskatchewan). They winter in the upper Amazon Basin of South America, primarily in Peru, north-eastern Ecuador, and north-western Brazil.
Chimney Swifts arrive on their breeding grounds in late March to late May and form pairs shortly after arrival. Pairs inspect many potential nest sites before settling on a final location that is well-protected from the outside environment. Nests are built by both the male and female by cementing together small twigs with saliva. Historically, most nests were built in natural formations – large hollow trees, tree cavities, and caves. However, the vast majority of modern nests are made in human created environments, such as chimneys, air vents, wells, garages, lighthouses, and silos.
Females lay 4-5 white eggs in the nest which are incubated by both parents. Eggs hatch after approximately 19 days and nestlings are fed by both parents. Notably, individuals from one pair (usually the male) may cooperatively help another pair with egg incubation and care of their young. After another 19 days young usually leave the nest, though are not capable of flight for an additional 10 days.
Birds breeding in Nova Scotia usually depart for their wintering grounds from late July to October. During migration these birds tend to form large flocks that travel together, flying during the day and roosting at night.
The Chimney Swift population declined precipitously between 1968 and 2005 by 95%. In Canada, the annual rate of decline between 2002 and 2012 was 4.04%, with a higher rate of 8.71% in Nova Scotia.
The most likely cause of this decline is the loss and degradation of suitable habitat. Suitable chimneys that provide roosting and breeding sites for these birds are declining as heating regimes change from wood burning to oil and electric heating. Additionally, many modern chimneys now have covers that prevent entry by animals, including swifts.
The industrial use of insecticides on agricultural lands has reduced populations of flying insects in North America, which Chimney Swifts feed upon. Specifically, the use of DDT in the mid-1900s is thought to have negatively affected the species. However, the specific implications of pesticide use on Chimney Swifts remain unclear.
Conservation status of the Chimney Swift both nationally and in Atlantic Canada:
|SARA||Threatened (Schedule 1)|