Saturday, 2 February 2013

Barn Swallow

order : Passeriformes      Genus & Species : Hirundinidae     Family : Hirundo rustica

The twittering calls and aerial acrobatics of returning swallows, as they swoop and twist to catch insects with graceful ease, are a herald of spring in northern regions. Scythe-like wings and elongated tail streamers give the barn swallow the maneuverability it needs to pursue and catch insects on the wing. They found in summer throughout North America, Asia and Europe — in open country, farmland, grassland and parks, wherever there are suitable nesting sites; winters in South America, southern Africa and Asia. 

Habitat : The supply of flying insects and availability of nesting sites are important factors determining the northern location of the swallow in summer. Insects are abundant over low, lush vegetation and shallow water, so pastures, fields, meadows and river valleys are preferred domain, especially where barns and sheds provide nesting sites nearby. Bare branches, overhead wires and roof-ridges are also useful places to rest and preen in the sun. Human activities, such as building and settlement, have helped release the species from its dependency on traditional nesting sites, such as cliffs and caves. In its southern winter habitat, the swallow finds rich insect-hunting grounds on stock-ranching land. 
Food & Feeding : The swallow feeds on flying insects, especially flies, which it captures in aerial pursuit. It favors large insects, such as bluebottles, hoverflies and beetles; in subtropical wintering grounds it also eats termites, grasshoppers and flying ants. In any habitat, the bird often follows grazing animals — whether farm cattle or zebras — to take insects stirred up by their hoofs. In poor weather, the bird may also dip into flowers to pick off insects or land on beaches to eat sandhoppers. When there are young to be fed, feeding is even busier. Large, stout-bodied flies are the main food for early summer broods, but smaller prey, such as swarming greenfly, become more important for later broods. The swallow catches several insects at a time and compresses them into a ball in the throat to feed to the nestlings. 
Behavior : Through the year, the swallow spends much time preening its feathers with its bill to keep them in peak flight condition. The bird also bathes by dipping into water while in flight. The swallow is highly social. In the summer, it can often be seen feeding in large flocks, uttering busy “witt-witt” calls to keep in contact with others. Colder weather in autumn brings a sharp decline in flying insects. Accordingly, the swallow flies south, setting off in small groups to spend the winter in South America, southern Africa or southern Asia. The barn swallows return north in the spring in preparation for breeding. 
Breeding : Older birds are the first to return to the breeding grounds and take the best sites. Unpaired males make a nest, then display to attract a mate, circling near the nest and twittering loudly. If a female is attracted, the male shows her the nest as proof of his prowess and they then mate.The female lays four or five eggs at daily intervals. She incubates after laying the last egg, so all the eggs hatch together two weeks later. Young are fed by both parents and grow rapidly. They first fly in three weeks and are fed for another week, but may stay nearby for another month. Early nesters can then rear a second clutch, even a third in good summers. Pairs often stay together for life, but because the swallow has an average lifespan of only 19 months, many adults have to seek a new mate the following breeding season. 

Beak : The small, flattened beak has a wide gape to help scoop up insects on the wing. 
Wings : The swallow’s long, tapering wings make it agile, but this bird isn’t particularly fast, reaching flying speeds of only about 18 mph. 
Feet : Long, narrow toes are adapted for perching on branches, cliffs and wires. On the ground, the bird shuffles on its short legs. 
Tail : Elongated feathers help the swallow slow down or turn rapidly. Extra-long tail streamers on a male show a prospective mate that he is healthy and fit to breed. 

Weight : 0.6–0.7 oz. 
Length : 6.6-7.3"
Wingspan : 13-13.6" 
Sexual Maturity : 1 year
Breeding Season : March–September 

When swallows disappeared from northern regions in fall, it was once thought that they buried themselves in the mud or hid in caves to hibernate through the winter.

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