Barn and Cliff Swallows

Barn Swallow

Figure 1: Drawing Credit - Elva Hamerstrom Paulson

Cliff Swallow

Figure 2: Drawing Credit - Elva Hamerstrom Paulson

Overview

Swallows are migratory songbirds that are found in Maine from spring to early fall. They are sparrow-sized birds with long, pointed wings and streamlined bodies developed for fast, acrobatic flight. You can see them swooping over fields, orchards, lakes, and anywhere else that flying insects are abundant.

Five species of swallows breed in Maine. A field guide may be helpful for identification of these and other swallow species, and for learning about their distribution throughout North America. (See "Additional Information" at the end of this article.) Of the five species, barn and cliff swallows regularly build mud nests attached to buildings, a process that sometimes brings them into conflict with humans. Because of their close association with humans, these two species are profiled here.

The barn swallow (Hirundo rustica) is a distinctive bird with bold plumage and a long, slender, deeply forked tail. It has blue-black upper parts, a reddish throat and breast, and a rust or buff colored belly. Females are slightly duller and shorter-tailed than males. Nests are made of mud pellets and some fibrous material and are often built under eaves, bridges, docks, in barns and garages, or other structures. (Fig. 1)

The cliff swallow (Petrochelidon pyrrhonota) looks somewhat like the barn swallow, but has relatively broad, round wings and a short, squared-off tail. The adult has a deep blue back, wings and crown. The belly is light, the forehead white, and the rump pale. (Fig. 2)

Facts about Swallows

Food and Feeding Behavior

  • Swallows are insectivores, catching a variety of prey midair with their wide-gaped bills and expert flight. Barn swallows eat some berries, seeds and dead insects from the ground, particularly during bad weather.
  • Swallows will fly several miles from their nest site to forage.
  • Long periods of continuous rainfall make it difficult for adult swallows to find food, occasionally causing young birds to die.
  • Swallows drink mid-flight; as they fly over water they dip their bill to the surface to drink.

Nest and Nest Sites

  • Barn and cliff swallows construct nests from mud pellets that they collect in their beaks.
  • Barn swallow nests are cup shaped (Fig. 1); cliff swallow nests are gourd-shaped (Fig. 2). Both species line the inner cup with grass, hair and feathers.
  • Historically, both barn and cliff swallows used cliffs and vertical banks protected from rain as nesting sites.
  • Today, barn swallows almost always build nests on eaves, bridges or docks, or in structures such as barns and garages that have a ledge (to support the nest), a vertical wall (to which it can be attached), and a roof.
  • Cliff swallows build their nests on vertical walls, either natural or constructed, frequently with some sort of sheltering overhang. They regularly use bridges, barns, and other large buildings. They construct the nests from mud pellets and some fibrous material. A large nest may contain a thousand pellets or more, each representing a trip to the source of mud (Fig. 2).
  • A pair of barn swallows usually nests by itself; cliff swallows nest in colonies that may contain a dozen to more than five hundred nesting pairs.
  • Barn and cliff swallow nests are prone to external parasite infestations. If parasite populations become too great, both species will prematurely desert their nests, abandoning their young. Colonies may not be reoccupied because of heavy infestations.

Reproduction

  • The nesting and breeding cycle, from the start of nest building to the departure of young, lasts 44 to 58 days.
  • Both the male and the female build the nest (beginning in early April), incubate the three to five eggs (which hatch after 12 to 17 days), and care for the young (which fly at 20 to 25 days).
  • After learning to fly, the young remain in or near the nest, to be fed by parents and to roost at night. They leave the nest after a few days and will remain in the area for several weeks.
  • Brood parasitism is common among cliff swallows. A female will lay eggs in the nest of other females and will also carry its own eggs in its beak to the nest of others.
  • Barn and cliff swallows can raise two clutches per year. Re-nesting will occur if nests or eggs are destroyed. For example, nests may fall because they were built too rapidly, or may crumble because of prolonged wet or humid weather.

Mortality and Longevity

  • Young swallows may fall out of their nests or die from nest infestations of blowfly and other parasitic insects and mites.
  • Young may also succumb to severe hot or cold temperatures, a fall from the nest, and predators such as crows, ravens, magpies, starlings, house sparrows, domestic cats, rats and tree squirrels.

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Viewing Swallows

You can enjoy the flowing flight of swallows from dawn to dusk. Barn swallows are agile flyers that come to within inches of the ground to catch flying insects. Cliff swallows glide, soar, and circle more than barn swallows do, and are often seen higher in the sky. Swallows perch on utility wires, TV antennas, and dead branches in large trees. You can observe young swallows sticking their heads out of the nest, begging for food when a parent arrives.

Nest Building

Gathering mud and constructing the nest is a social activity for cliff swallows; unmated birds may build a nest, even though it will go unused.

Barn and cliff swallows travel up to half a mile to gather mud from ponds, puddles and ditches. To find one of their collection sites, watch where they land on the ground (they rarely do so except when nest building). They stay for about a minute, poking their beaks into the mud several times to get a good load, then fly back to the nest site. The ground will be pocked with numerous small holes.

You may also see swallows carrying feathers or grass, materials that they use in the final stage of nest building.

Calls and Songs

The barn swallow's song is a series of twitters and gurgles. The bird emits a soft wit wit call when feeding with other swallows and approaching their nests. It gives a louder version of this call when possible danger (such as a human) approaches its nest.

The cliff swallow's song is a series of thin, strained, drawn-out rattling sounds that is shorter and simpler than that of the barn swallow. The call is a low, soft, husky verr or churr, sounding like the squeaking of a door with rusty hinges.

The Marvel of Migration

Each year, almost half the bird species that breed in Maine migrate south to tropical Central and South America. This migration is one of the wonders of the natural world. These birds, called "neotropical migrants," spend six or more months in southern locations before returning north in spring to mate and rear young.

Swallows are usually the first to begin the southern migration in mid-August. They gather in large groups (sometimes as many as a thousand birds) on telephone wires and other perches before departing. Barn and cliff swallows winter in Central and South America. The main reason they head south every year is that there are few insects to eat in the north during winter; avoiding cold temperatures is actually a less important reason.

Barn and cliff swallows begin their return to northern climes in late winter and early spring. They migrate during the day, catching flying insects along the way. They will normally not move into an area unless flying insects are available for food, which occurs after a few days of relatively warm weather of 60 degrees F or warmer. Depending on weather conditions, swallows are first spotted in southern Maine in late March or early April.

The famous swallows of Capistrano, California are cliff swallows. Contrary to legend, they return to Capistrano in late February, considerably earlier than the fabled March 19th date.

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Preventing Conflicts

Many people enjoy watching swallows nest on or around their homes. Colonies of cliff swallows on school grounds can provide excellent opportunities for study. The anticipation of the swallows' arrival in the spring is exciting, watching parents feeding their young is a wonderful sight, and swallows consume thousands of flying insects that are considered pests. The barn swallow's close association with humans in Europe goes back more than two thousand years.

It has been speculated that one reason swallows choose to nest on door stoops, light fixtures, and porch fronts is because the closeness to humans keeps away crows and other predators. The birds will even risk cat predation and human vandalism, and place nests close to the ground if the location is frequented by humans. Thus, if you thwart a barn or cliff swallow's nesting effort, you may be denying the birds their only chance at successful reproduction.

To prevent conflicts or remedy problems:

Manage swallow droppings: Conflicts with swallows occur when these birds nest close to humans, primarily because of the droppings and other debris they deposit.

When swallows first hatch, the parents eat their droppings, which keeps the nest clean and free of insects. After a few days, the adults carry the droppings (which are encased in a fecal sac made from a clean mucous membrane) away from the nest to prevent detection by predators. After about the twelfth day, the young back up to the edge of the nest and defecate out over the rim.

Placing newspaper or similar material where droppings accumulate can solve the problem. As necessary, the paper and droppings can be added to a compost pile, dug into the ground (droppings make wonderful fertilizer), or placed in the garbage. Similarly, a blanket or tarp can be used to cover a car or structure, and moved when needed.

Figure 3b: Drawing Credit Jenifer Rees

Figure 3a: Drawing Credit Jenifer Rees

Another solution is to install a board under the nest(s) to catch the droppings and debris (Fig. 3). Because of its nearness to the nest, the board should be cleaned as needed to prevent infestations of insects and mites that may live in the accumulated debris. Before attaching the board, observe the swallows comings and goings to prevent installing something that could interfere with their access to the nest.

To contain barn swallow droppings, mount a board under the nest using eye screws and wire. Place newspaper or a piece of thin paneling on the board and remove it when it needs cleaning. A long board or other material can be used under groups of cliff swallow nests. The board should be several feet below the nest and narrow enough that it does not interfere with the bird's approach, landing and departure. (Fig. 3)

Create a barrier: If you do not want a swallow to nest on a building or other structure, install a barrier. Barriers include any physical structure placed between the swallow and the structure. A permit is not required for this method if it is done before the birds arrive, during nest-building when there are no eggs or young in the nest, or after the birds have left for the winter. If swallows have eggs or young in the nest, you may not exclude birds without a permit (see "Legal Status").

Figure 4: Drawing Credit - Hygnstrom

To prevent barn swallows from nesting on door jambs, window jambs, or other sites on the side of a building, cover the area with bird-netting or one-inch mesh chicken wire. Drape the material from the outer edge of an eave down to the side of the building (Fig. 4). Remove wrinkles and folds that could trap or entangle swallows or other birds.

To deter swallows from nesting on structures, attach bird netting or chicken wire from the outer edge of the eave down to the side of the building. Alternatively, create a small curtain of netting. (Fig. 4)

Bird netting and chicken wire are available from nurseries, hardware stores, and farm supply centers. Some pest-control companies sell a heavy-duty netting material with a larger mesh than the common black netting used to protect fruit from birds. The larger netting is not as likely to create problems for songbirds, which sometimes get caught in the smaller mesh netting. To find the product, search the Internet for "bird control supplies" or look in your phone book under "Pest Control".

Attach the barrier using staples, brass cup-hooks, adhesive backed hook-and-loop Velcro, trash-bag ties, or other fasteners. To avoid unsightly rust stains, use only rust-resistant fasteners. The barrier may also be first stapled to or wrapped once or twice around wood laths, which are then attached to the structure. This technique can also be modified to keep swallows from entering a breeze-way or similar site to nest.

Or, hang a curtain of bird netting or chicken wire from the eave (Fig. 4). Place the curtain be three to four inches from the wall and extend it 18 inches or more below the eave. A well-placed curtain can be nearly invisible from even fifty feet because it occupies a shaded area that becomes obscured by shadows.

Figure 5: Drawing Credit - LFWITPN

For small areas, install aluminum foil, aluminum flashing, or heavy plastic over the targeted area. The smooth surface will prevent the birds from sticking mud to the wall. Painting the area with a glossy latex paint may also be effective.

You can offer barn swallows an optional nesting site by constructing a nest platform (Fig. 5).

A nesting platform designed for robins and barn swallows. (Fig. 5)

Note: Hawk, owl, and snake models, noisemakers, revolving lights, red-and-silver flash tape, and hanging pie tins are unlikely to deter swallows.

Remove the nest only if it is inactive because all swallows are protected under law: Do not disturb them once they are active in the nest. (see "Legal Status")

You can wash down inactive nests with a hose or knock them down with a pole. Because swallows persist at rebuilding, you must continue to remove the nest mud for several days until the birds stop. Swallows are strongly attracted to old nests or to the remnants of deteriorated nests, so all traces of mud should be removed.

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Public Health Concerns

Swallows are not a significant source of any infectious disease that can be transmitted to humans or domestic animals.

Anyone handling a river otter should wear rubber gloves, and wash their hands well when finished.

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Legal Status

Swallows are federally protected. Any permit to lethally control these species would need to be issued from the U.S. Fish and Wildlife Service, and would only be issued in very extreme cases. Some examples are concerns for aircraft safety from a nesting colony at an airport or potential food contamination from a colony over a loading area at a food-processing center.

In most cases a permit for lethal control will not be issued for swallows nesting on a residence or other buildings and causing aesthetic damage.

A permit is not required to remove swallow nests under construction that do not contain an adult, any new eggs or young, or nests abandoned after the breeding season. If an adult swallow is occupying a half-built nest, or a fully built nest without eggs, then the law protects it.

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Additional Information

Books

The Birder's Handbook: A Field Guide to the Natural History of North American Birds
Written by: Paul R. Ehrlich, et al.
New York: Simon & Schuster, 1988.

A Field Guide to Eastern Birds
Written by: Roger Tory Peterson
Boston: Houghton Mifflin, 1990.
Washington, DC: National Geographic Society, 2002.

Audubon Society Field Guide to North American Birds -- Eastern Region
Written by: Miklos D.F. Edvardy
New York: Alfred A. Knopf, 1977.

New England Wildlife, Habitat, Natural History, and Distribution
Written by: Richard DeGraff, and Mariko Yamasaki
University Press of New England, 2001.
(Available from: www.upne.com)

Internet Resources

Adapted from: "Living with Wildlife in the Pacific Northwest"
(see Washington Department of Fish and Wildlife)

Written by: Russell Link, Wildlife Biologist, Email Russell Link, with assistance from WDFW Biologists Rich Beausoleil and Rocky Spencer

Design and layout: Peggy Ushakoff, ITT2

Illustrations: As credited

Copyright 2005 by the Washington Department of Fish and Wildlife