Cliff Swallow

About

The Cliff Swallow is a highly social migratory passerine bird known for its distinctive gourd-shaped mud nests built in large colonies, often under eaves, bridges, or natural cliff faces. They are aerial insectivores, spending much of their time foraging on the wing.

Size & lifespan

Length

13-15 cm (5.1-5.9 in)

Wingspan

28-33 cm (11-13 in)

Weight

19-28 g (0.67-0.99 oz)

Lifespan

Typically 2-4 years in the wild, with a maximum recorded of 11 years.

Diet

Insectivore, primarily consuming flying insects.

Physical characteristics

Plumage

Adults have a dark, iridescent blue-black back and crown, a rufous (reddish-brown) throat and sides of the neck, a pale buffy-white belly, and a distinctive square-tipped tail. The most striking feature is the pale, often creamy-white, forehead patch and a dark chestnut patch on the rump.

Beak shape

Small, flattened, and triangular, adapted for catching insects in flight. Black in color.

Eye color

Dark brown.

Leg color

Dark gray to black.

Distinguishing features

Creamy-white forehead patch, dark chestnut rump patch, square-tipped tail (not forked like Barn Swallow), and a dark throat contrasting with a pale belly. The overall shape is stocky compared to other swallows.

Juvenile appearance

Juveniles resemble adults but have duller plumage. The forehead patch is less distinct and often buffy or brownish, and the throat and rump patches are paler and less defined. They may also show pale feather edgings on the back and wings.

Seasonal changes

No significant seasonal plumage changes. Plumage may appear slightly duller due to wear towards the end of the breeding season.

Sexual dimorphism

Males and females are generally monomorphic in plumage, appearing very similar. Males may have slightly brighter iridescence on the back.

How to identify

1. 1

   Forehead Patch

   Look for the distinctive pale, often creamy-white, patch on the forehead, contrasting with the dark crown.

2. 2

   Rump Patch

   Identify the dark chestnut-colored patch on the rump, which is a key field mark.

3. 3

   Tail Shape

   Observe the tail, which is square-tipped or only very slightly notched, unlike the deeply forked tail of the Barn Swallow.

4. 4

   Throat Color

   Note the dark rufous (reddish-brown) throat, which contrasts with the pale belly.

5. 5

   Nesting Behavior

   Their gourd-shaped mud nests built in large colonies under eaves, bridges, or cliffs are a strong indicator of their presence.

6. 6

   Flight Style

   Watch for their agile, often swirling flight in flocks, especially when foraging for insects.

Habitat & range

Biomes

Open country, grasslands, agricultural areas, urban and suburban environments, often near water sources.

Geographic range

Breeds across most of North America, from Alaska and Canada south through the United States and into Mexico. Winters in South America, primarily in the southern Amazon basin, Argentina, and Brazil.

Elevation range

From sea level up to approximately 3,000 meters (10,000 feet) in mountainous regions during breeding season.

Preferred environments

Requires vertical surfaces for nesting (cliffs, bridges, buildings) and open areas for foraging on flying insects. Often found near water bodies which provide insect prey and mud for nest construction.

Behavior

Activity time

Diurnal.

Feeding habits

Exclusively aerial insectivores, catching insects on the wing. They forage in flocks, often circling high in the sky or skimming low over water and fields. Diet includes flies, beetles, bees, wasps, and true bugs.

Social behavior

Highly colonial breeders, forming large colonies that can number in the thousands of nests. They also forage and migrate in large flocks. This coloniality helps in predator defense and information sharing about food sources.

Flight pattern

Graceful and agile flight, characterized by rapid wing beats interspersed with glides. They often fly in tight, swirling flocks, especially when foraging or approaching colonies.

Migration pattern

Long-distance Neotropical migrant. They breed in North America and migrate south to winter in South America. Fall migration typically occurs from late July to September, and spring migration from March to May.

Territoriality

While highly colonial, individual pairs defend a small area immediately around their nest. Foraging areas are shared.

Breeding & reproduction

Breeding season

Typically May to August, with peak activity in June and July.

Nesting habits

Builds distinctive retort-shaped (gourd-shaped) nests made of mud pellets, often mixed with grass. Nests are attached to vertical surfaces under overhangs, such as cliffs, bridges, culverts, and buildings. They are built communally in dense colonies, sometimes touching each other.

Clutch size

3-6 eggs, typically 4-5.

Egg description

3-6 eggs, white with fine reddish-brown or purplish spots, particularly concentrated at the larger end. Eggs are oval-shaped.

Incubation period

13-16 days, primarily by the female.

Fledging period

20-26 days after hatching. Young are fed by both parents.

Parental care

Both parents participate in nest building, incubation (though female does most), and feeding of the young. Young birds often return to the colony after fledging and may be fed by parents for a short period.

Where to find

Field tips

1. Look for colonies. Cliff Swallows are highly colonial. If you find one nest, there are likely many more nearby. Look for clusters of mud nests.
2. Observe flight patterns. Watch for their characteristic swirling, agile flight as they forage for insects. They often fly in groups.
3. Listen for calls. Their chattering and squeaky calls are often heard around colonies, especially during the breeding season.
4. Check under structures. Systematically check under bridges, culverts, and the eaves of buildings for their distinctive mud nests.
5. Visit during breeding season. The best time to observe them is during their breeding season (May-August) when they are actively nesting and raising young.

Similar species

Quick facts

Diet:

Flying insects

Nesting:

Gourd-shaped mud nests in colonies

Migration:

Long-distance Neotropical migrant

Sociality:

Highly colonial

Distinguishing Feature:

Pale forehead, dark chestnut rump, square tail

Fun facts

• Cliff Swallows are known for their 'eavesdropping' behavior, where individuals observe the foraging success of their neighbors to locate good feeding grounds.
• They can travel long distances, sometimes over 1,000 km (620 miles), to find suitable mud for nest construction.
• Colonies can be massive, sometimes containing thousands of nests, which helps in collective defense against predators like snakes and raptors.
• Their nests are often parasitized by swallow bugs (Oeciacus vicarius), which can significantly impact reproductive success, especially in older nests.
• Cliff Swallows have adapted well to human-made structures, with bridges and buildings now providing more nesting sites than natural cliffs in many areas.

Scientific classification

Kingdom

Animalia

Phylum

Chordata

Class

Aves

Order

Passeriformes

Family

Hirundinidae

Genus

Petrochelidon

Species

Petrochelidon pyrrhonota

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