Instead, they have adapted to cling to rough vertical surfaces. Historically they roosted in the hollows of large trees, but when the forests were cut and so many landmark trees in urban areas disappeared, the Chimney Swifts turned to chimneys as substitutes for tree hollows. Now, as old chimneys are torn down, capped, or lined with metal, they find fewer places to roost and build nests to raise their young. This loss of habitat is among the factors threatening their continued existence.
In spring, the Swifts arrive and build nests in chimneys. In late summer and fall, large groups gather in chimneys in preparation for their annual migration south. Around dusk, one can see hundreds spiraling around the chimney at 415 before they swoop down into the chimney for the night. Washtenaw Audubon has recently counted 1,400 Swifts swooping down into the chimney at 415 at dusk on a fall evening.
In spring, the Swifts arrive and build nests in chimneys. In late summer and fall, large groups gather in chimneys in preparation for their annual migration south. Around dusk, one can see hundreds spiraling around the chimney at 415 before they swoop down into the chimney for the night. Washtenaw Audubon has recently counted 1,400 Swifts swooping down into the chimney at 415 at dusk on a fall evening.