Apr 9, 2014 | Featured Web Article

Chimney Swift Nests: One per Chimney

Chimney swifts are most common in cities, where they use their namesake chimneys and other hollow structures for nesting and roosting. The chimney swift is the only eastern swift species.

Even though hundreds or even thousands of chimney swifts drop into a single chimney to roost at dusk during fall migration, that chimney will host only one chimney swift nest during breeding season.

Chimney swifts are not colonial nesters, although a breeding pair will permit unmated swifts to roost in "their" chimney while nesting is active.

Historically, chimney swifts nested in scattered hollow trees in old-growth forests—and some still do, as well as in abandoned pileated woodpecker cavities. The species adapted well to European settlement and the increase of homes and other buildings with smokestacks and other sheltered vertical structures, such as air vents, abandoned water wells, garages, barns, silos, old buildings, etc. Darkness and shelter from sun, wind, and rain are the required characteristics of a chimney swift nest site.

Inside a suitable structure, a chimney swift nest is built of loosely woven twigs held together and to the vertical wall with the swift's glue-like saliva. Both parents build the nest, and egg laying begins even before nest construction is finished.

In the past few decades, the chimney swift population has declined as old chimneys deteriorate, and new ones are less suitable for nest sites. Many new buildings lack chimneys altogether. Some communities, organizations, and even private individuals have built standalone towers to provide a roost site for many chimney swifts, and a nest site for just one pair of swifts.

For more information on chimney swifts, please visit www.chimneyswifts.org.

About Dawn Hewitt

Dawn Hewitt is the editor at Watching Backyard Birds and Bird Watcher's Digest. She has been watching birds since 1978, and wrote a weekly birding column for The Herald-Times, a daily newspaper in Bloomington, Indiana, for 11 years.

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