Cliff Swallow (Petrochelidon pyrrhonota): The Social Bird with the Gourd-Shaped Nest
The Cliff Swallow is a highly social bird, famous for its colonial nests and distinctive square tail.
Introducing the Cliff Swallow
The Cliff Swallow (Petrochelidon pyrrhonota) is a truly remarkable bird, a master of social engineering and architectural prowess. Unlike its more solitary cousins, this swallow lives in bustling colonies that can number in the thousands. The American Cliff Swallow is renowned for its incredible nests - gourd-shaped mud structures clustered together under bridges, on cliff faces, and beneath the eaves of buildings. Their constant activity and chattering calls make any Cliff Swallow colony a captivating spectacle to observe.
Identification: Square Tail & Pale Rump
At a glance, Cliff Swallows can look similar to other swallows, but a few key features make them easy to identify.
Key Features
Tail: The single best field mark. The tail is short and squared-off at the end, not long and forked.
Rump: A pale, buffy or peachy patch on its lower back, just above the tail. This patch is very noticeable in flight.
Forehead: A distinct creamy or whitish patch above the bill.
Throat: Dark and chestnut-colored, which can look black from a distance.
Back: A deep, steely blue like other swallows.
These features distinguish the Cliff Swallow bird from its more common relative, the Barn Swallow.
Cliff Swallow vs. Barn Swallow: Key Differences
Confusing these two swallows birds is common. This table breaks down the essential differences to look for.
Feature
Cliff Swallow
Barn Swallow
Tail Shape
Short and square
Long and deeply forked
Rump Patch
Pale / Buff-colored patch
Dark (same color as back)
Throat Color
Dark / Chestnut
Cinnamon / Reddish
Nest Shape & Location
Gourd-shaped, enclosed mud nest in large colonies.
Open mud cup, often built singly inside structures.
For a complete guide on the other species, see our detailed page on the Barn Swallow.
The Famous Cliff Swallow Nest & Colonies
The Cliff Swallow nest is one of the most remarkable structures in the avian world. These birds are master masons.
Nest Construction
Both male and female build the nest from hundreds of mud pellets. They create a fully enclosed, gourd-shaped chamber with a small entrance tunnel on the side. This provides excellent protection from predators and the elements. Building a single nest can take up to a week.
The incredible colonial nests of Cliff Swallows are a testament to their social nature and building skills.
Colonial Living
Cliff Swallows are highly social and nest in dense colonies, with nests often stuck right next to each other. These colonies can be found on natural cliffs but are now more common on man-made structures like bridges, overpasses, and large buildings. Living in a colony helps them find food more efficiently and provides shared defense against predators.
Habitat & Diet
Cliff Swallows thrive in open to semi-open habitats across North America.
Habitat
Their primary requirements are a vertical surface for nesting (cliffs, buildings), a nearby source of mud for nest-building, and open areas for foraging. They are commonly found near rivers, lakes, and in agricultural landscapes.
Diet
Like all swallows, they are aerial insectivores. They feed on swarming insects, catching them in mid-air. Their diet consists of flies, beetles, bees, and other flying insects. They often forage in large flocks over water or fields.
Migration
Cliff Swallows are long-distance migrants. They breed across most of North America and spend their winters far to the south, primarily in South America. They migrate in large flocks, a spectacular sight in both spring and fall.
Conservation Status
The Cliff Swallow is currently listed as a species of "Least Concern," and its population is considered stable or even increasing. Their ability to adapt from natural cliffs to man-made structures has allowed them to expand their range. They are protected under the Migratory Bird Treaty Act, which makes it illegal to disturb their nests during the breeding season.
