Cave Swallow

Guide to North American Birds

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Adult. Photo: Rick and Nora Bowers/Alamy

As recently as the 1960s, this was a rare bird in the United States. It nested only in a few southwestern caves, plastering its cuplike mud nest against the walls in the dimly lit interior. Since then it has "learned" to nest in artificial sites, in culverts and under bridges, and it has become a common summer bird across much of Texas and southern New Mexico (with an outlying colony in Florida). In some places, Cave Swallows may actively compete with Cliff Swallows for these artificial nest sites.

Conservation status	Range has expanded and population has greatly increased in recent decades.
Family	Swallows
Habitat	Semi-open country. Forages over any kind of open or semi-open terrain, especially near water. Breeding was formerly limited by scarcity of nest sites in natural caves or sinkholes. Now nests under bridges and in culverts, buildings, silos, many other artificial sites, allowing species to spread into new habitats.

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Feeding Behavior

Forages almost entirely in flight. May forage low over water or may forage much higher, mainly in clear warm weather. Often forages in flocks.

Eggs

3-4, sometimes 2-5. White, finely spotted with brown and purple. Incubation is probably by both parents, thought to be about 15 days. Young: Both parents bring food for nestlings. Young leave nest at about 20-26 days.

Young

Both parents bring food for nestlings. Young leave nest at about 20-26 days.

Diet

Insects. Diet not known in detail, but feeds on a wide variety of flying insects, including beetles, flies, true bugs, wasps, bees, winged ants, grasshoppers, lacewings, moths, and others.

Nesting

Typically nests in colonies, sometimes with hundreds of pairs. Nest: Natural site is on steep wall of cave or sinkhole, in area away from entrance but with at least some light. Artificial sites are on vertical surfaces in culverts, under bridges, or in buildings; in Yucatan Peninsula, may nest in ancient Mayan temples. In well-sheltered sites, nests may last for years and be used repeatedly. Nest (built by both sexes) is an open cup of mud plastered against wall. Birds in natural sites gather mud on cave bottom, where it often contains much bat guano. Nest is lined with grass, bark fibers, plant down, and feathers.

Illustration © David Allen Sibley.
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Text © Kenn Kaufman, adapted from
Lives of North American Birds

Migration

Small Florida population supposedly winters in West Indies. Winter range of southwestern birds poorly known. In recent years, has begun wintering regularly in Texas. A remarkable dispersal now brings numbers of Cave Swallows to the middle Atlantic Coast and parts of the Great Lakes, far north of their breeding range, almost every year in late fall.

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Migration

All Seasons - Common
All Seasons - Uncommon
Breeding - Common
Breeding - Uncommon
Winter - Common
Winter - Uncommon
Migration - Common
Migration - Uncommon

Songs and Calls

Series of squeaks, twitters, and warbles.

calls calls

Audio © Lang Elliott, Bob McGuire, Kevin Colver, Martyn Stewart and others.
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How Climate Change Will Reshape the Range of the Cave Swallow

Audubon’s scientists have used 140 million bird observations and sophisticated climate models to project how climate change will affect this bird’s range in the future.

Zoom in to see how this species’s current range will shift, expand, and contract under increased global temperatures.

Climate Threats Near You

Climate threats facing the Cave Swallow

Choose a temperature scenario below to see which threats will affect this species as warming increases. The same climate change-driven threats that put birds at risk will affect other wildlife and people, too.