Monday, May 21, 2012

Adirondack Birding: The Barn Swallow

Barn SwallowCoinciding with the onset of bug season in the Adirondacks is the return of our insect eating birds. While nearly all of these perching birds have an attractive musical call that announces their presence, most maintain a secretive routine so they are rarely spotted.

The swallows are the most visible bug consumers as their preference for perching in exposed places and feeding over open settings allows these skilled aerialists to be regularly seen.

Additionally, their habit of placing their nest close to human dwellings and in plain view of any passerby makes them well known to residents and visitors of the Park.
Among the various species of swallows that come to the Adirondacks to breed and raise their young is a colorful individual that often causes great irritation to those that attempt to maintain a clean boathouse. Also notorious for making an excessive mess throughout the summer around selected porches, woodsheds, open entryways, stables, and any other structures that provide some form of overhead cover is the barn swallow, the number one nuisance bug glutton of the region.

Two centuries ago, before there were permanent settlements in the Adirondacks, it is believed that the barn swallow placed its nest on small stone shelves jutting from the surface of a cliff that was protected from the weather by a rocky overhang. Because of the limited number of these sheltered stone faces, the barn swallow evolved the ability to nest close together so that numerous pairs of birds could utilize the same location for nesting.

As human dwellings began to be built along the shores of lakes and the edges of forest clearings, a multitude of new sites that better protected the nest from rain and strong winds became available. Because of the success of the nests placed in these timber frame barns, sheds, and lodges, traditional nesting sites were gradually abandoned in favor of certain man-made structures.

The creation of large open spaces also had a positive impact on the barn swallow population, as this bird prefers to forage over areas in which trees are few in number. Lakes, marshes, and bogs are all naturally occurring open sites that attract the barn swallow. Golf courses, airports, athletic fields, farms and pastures are other places in which this swallow may regularly be encountered.

Unlike many insect eaters, such as the warblers and vireos, that collect the bulk of their bugs from the surface of plants, the barn swallow targets insects that are in flight. Upon spotting a suitably sized invertebrate moving through the air, the barn swallow quickly alters its flight path in order to intercept the potential meal. The rapid change in its direction of flight gives the barn swallow, along with its other close relatives, the appearance of an accomplished and skilled aerial acrobat. The deeply forked tail, used to identify it, helps provide a more streamline body shape when turning and adds to its maneuverability in flight.

Shortly after the return of the swallows to the Adirondacks, pair formation occurs, and then the task of nest building commences. Once a suitable sheltered platform is located, the birds begin to form a base made from mud. The presence of patches of mud with a favorable texture is critical to this bird. Ordinarily, the edges of puddles in places of poor drainage, are visited for the mouthfuls of soft, watery soil used for the initial portion of its nursery. Muddy sections along the shores of lakes and rivers are also used if they happen to be close by. Eventually, pieces of dried grass and the stems of plants are used to reinforce this earthen framework as it hardens.

Because gobs of mud and pieces of grass and small twigs regularly fall from the mouth of the barn swallow as it flies to its nest, the area around its summer residence quickly becomes covered with these scraps. After the nest is finished and eggs are laid, there is continuous back and forth travel to the nest by both parents. However, immediately after exiting the nest, or just prior to a bird’s arrival, the time comes for the resident to expel bodily wastes from its system. This can compound the mess that the swallows create until the young birds fledge in August.

A colony of barn swallows is ideal to have residing in your general neighborhood, as the number of mosquitoes and other flying bugs they consume is tremendous. However, it is always better to have them nesting in a neighbor’s boathouse or barn for, like typical teenagers, they never clean up after themselves.

Illustration: Barn Swallow from Audubon ‘s Birds of America.

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Tom Kalinowski is an avid outdoor enthusiast who taught field biology and ecology at Saranac Lake High School for 33 years. He has written numerous articles on natural history for Adirondack Life, The Conservationist, and Adirondack Explorer magazines and a weekly nature column for the Lake Placid News. In addition, Tom’s books, An Adirondack Almanac, and his most recent work entitled Adirondack Nature Notes, focuses on various events that occur among the region’s flora and fauna during very specific times of the calendar year. He also spends time photographing wildlife. Tom’s pictures have appeared in various publications across the New York State.

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