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North­American­Swallows

Veronica Bowers

Natural History

There are approximately 90 species of swallows found worldwide, except in Antarctica, and the
greatest number of species is found in Africa. Eight of the 90 species occur in North America. All
North American swallows are migratory, spending the breeding season in the U.S. and migrating
as far as South America during the winter.
Swallows have long pointed wings, short bills, short legs, small delicate feet, and an anisodactyl
toe arrangement with three toes forward and one toe back. Swallows are more aerial than other
passerines and are graceful while in flight, much like swifts. All swallows are aerial insectivores,
frequenting open areas for foraging, often near bodies of water. Swallows feed almost exclusively
on flying insects. Tree Swallows are the only North American swallows known to occasionally
consume certain types of berries during the winter.
Some species, such as Tree and Violet‐green Swallows, nest in dispersed territories. Others, such
as Barn Swallows, nest in aggregated groups. Cliff and Bank Swallows nest in colonies. Nest sites
range from burrows to holes in trees, banks, and cliffs, to nest boxes or cup or gourd‐shaped nests
made of mud.
All species hatch altricial, naked, blind, and helpless young. Incubation ranges from 13 to
18 days. Both parents care for the young in all swallow species. Young swallows fledge the nest at
approximately 3 weeks of age.

­ Criteria­for Intervention

The mud nests of Barn and Cliff Swallows are frequently knocked down by humans. Nests can also
legitimately fall from structures on their own if an old nest was reused or there is a prolonged spell
of extreme weather such as intense rain or a heatwave.
If a Barn Swallow nest has fallen, the nest remained mostly intact, and the young in the nest are
uninjured, a nest replacement should be considered. To replace the nest, construct a cup‐shaped
basket out of 0.25 in. (0.5 cm) chicken wire and affix the basket in the exact location of the original
nest. Make sure the basket is free of sharp edges or protruding pieces of wire that could cause
injury to parent birds arriving at the nest or young in the nest. Insert the original nest with the

Hand-Rearing Birds, Second Edition. Edited by Rebecca S. Duerr and Laurie J. Gage.
© 2020 John Wiley & Sons, Inc. Published 2020 by John Wiley & Sons, Inc.