Compiled by Linda deKort
Selections from Cornell University Website

Like the legendary cliff swallows who loyally return each year to the mission in Capistrano, California, the swallows of the Flathead are arriving back at their predictable times. We may not greet them with the ringing of church bells, nor a huge fiesta, but their return is no less remarkable.

Swallows belong to the family Hirundinidae. All swallows forage for aerial insects and spend more time on the wing than any other songbirds in the world. Their short wide bills help them feed as they sweep through clouds of swarming insects near water and above the forest canopy. Many species roost at night on marsh reeds.

Among the swallows that return here each spring to breed are the Tree Swallow, Violet-green Swallow, Northern Rough-winged Swallow, Bank Swallow, Cliff Swallow, and Barn Swallow. Tree Swallows arrive first, about the first week in April. Just a bit later we see the Violet-greens. By the end of April, the Northern Rough-winged, the Cliff and the Barn Swallows are here. The Bank Swallows are the last to arrive, early in May. Our six species of swallows winter as far away as Central and South America; they will head south again in September. Until then, we have the opportunity to relish the aerial acrobatics of these elegant birds and to benefit from their mosquito hawking expertise. Swallows eat insects almost constantly while in flight. For this reason, attracting swallows may be one positive step to managing insects such as flying ants, termites, aphids, mosquitoes and gnats. On average, insects make up 99.8 percent of the swallow’s diet. A single Barn Swallow can consume 60 insects per hour or a whopping 850 per day. That’s 25,000 fewer insects per month that might have joined your summer bar-b-que.

Barn Swallows (Hirundo rustica) provided our family with our first close up and personal encounter with the swallows of the Flathead. This article is devoted to them. (Next spring, you can anticipate an article on one of our other amazing swallow species.) The Barn Swallow is the only North American swallow with a deeply forked tail. The male’s tail is somewhat longer than the female’s and juveniles don’t develop the long tail until they reach adulthood after one year. The male usually has a rich orange breast and belly; the female has a whitish belly. Both sexes have a deep rust-colored throat and their upper body glistens in iridescent blue-black. They are about 5 to 7 inches long, and about 3/4 ounce. They have slender pointed wings and their flight seems easier and more flowing than other swallows.  They are also the fastest of the swallows and have been clocked flying 46 mph!

Because of their preferred nesting sites, Barn Swallows have undoubtedly provided many families with opportunities to view courtship, incubation and rearing. Barn Swallows were originally cave breeders but now build their nests of mud almost exclusively under manmade structures such as barn rafters (hence their name), bridges and eaves.

If you have a window positioned just in front of a chosen nest site, you are treated to the best of reality shows. Both parents help with the nest building. As the parents pick up mud and carry it in their mouths, they form it into small pellets. If you look closely at a swallow nest, you’ll see many individual mud pellets, as many as 1,000, that make up the nest. The open cup on the top of the mass of mud is lined with feathers, horse hair, and other soft items. It might take the parents a full week to construct the nest, with no time off on weekends. The pair seem to work from dawn to dusk with only a brief rest in the middle of the day. The female lays four or five brown-speckled white eggs. The incubation period is about two weeks, and both parents take unequal turns sitting on eggs and providing food for each other. The female does most of the incubation. They both rest at night beside each other in the nest, a picture of contentment and loyalty. But don’t be deceived; there is much more to the courtship of barn swallows than this tranquil scene suggests. Science magazine reported last fall that females constantly judge their mates by their looks, in particular by the reddish color of the males’ breast and belly feathers. Females mated to males with paler feathers were more likely to secretly copulate with another male. Researchers from the Lab of Ornithology of Cornell University used nontoxic markers to enhance the feather color of some of the males in the study. All of the swallows remained paired with their original mates, but DNA testing revealed that females paired to males with the reddest feathers cheated less. As a result, those males fathered a greater proportion of young in their brood. Perhaps the intensity of the reddish color is an indicator of the male’s health, status, and ability to raise young. The long tail of a Barn Swallow also may indicate the quality of the individual bird; another study revealed that females prefer to mate with males that have the longest and most symmetrical tails. Unmated male Barn Swallows have been observed killing nestlings of nesting pairs, which often succeeds in breaking up the pairs and affords the culprits the opportunity to mate. So among barn swallows, color matters and all is fair in love and war.

The young stay in the nest about 3 weeks after hatching. Both parents provide care. The little ones, when fully fledged, are enticed to fly by their parents. As the young improve in flying, they are often fed on the wing by the parent birds. In the evening the family retires to the breeding place, and usually stays there until mid- August when migration activity begins. During this time, those beautiful mud-based nests can become regarded as an unattractive decoration, as the fledglings drop their “calling cards” below. Despite this annoyance, remember that not only are swallow nests truly a sign of good luck, their inhabitants help keep down the mosquito population.

Swallows, their active nests and eggs are protected by the federal Migratory Bird Treaty Act and may not be destroyed. If, however, you find a swallow nest being constructed near your front door, try placing an artificial nest off to one side of the door or even on a different wall; it may be the surest way to coax the swallows to move, because barn swallows seem to prefer a distance of several feet between nests.

As you watch the swallows returning to Flathead Valley this spring, consider their beauty, their intrigue and their mosquito-eating fervor. Then get out the bells and ring in their return.

One thought on “Barn Swallow

  1. […] for the Flathead Audubon Society, Linda deKort states that “…insects make up 99.8 percent of the swallow’s diet”. In short, […]

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