Saturday, 2 February 2013

Bank Swallow

order : Passeriformes      Genus & Species : Hirundinidae     Family : Riparia riparia

The bank swallow lives almost entirely in the air, wheeling and dipping as it chases its tiny insect prey. Only in the breeding season does it spend part of the time on the ground. Long, streamlined wings and a forked tail give the bank swallow a fast, buoyant flight and the maneuverability to catch flying insects. They found in the summer throughout temperate regions of North America, Europe and Asia, including parts of China; spends winter months in South America, Africa and parts of central Asia. 

Habitat : The bank swallow prefers open country, often near streams, rivers and lakes, where it has space to fly in pursuit of insects. It needs trees, bushes or man-made perching places to rest on, but tends to avoid thick woodland, built-up areas, highlands and dry regions. In summer breeding seasons, the bank swallow’s habitat is determined by the presence of soft, sandy banks in which it builds nesting burrows. It’s now found near riverbanks, earth cliffs and old sand pits. 
Food & Feeding : The swallow feeds on flying insects, especially flies, catching them by swooping down with an open bill. It sometimes eats grasshoppers, dragonflies and beetles. The bank swallow also drinks while in flight by flying close to the water and scooping it up in the lower half of its bill. When there are young to be fed, the adults fly in frequent food-gathering missions — more than ten per hour — and they catch most insects in the late morning and afternoon. On average, a brood of young bank swallows may be brought as many as 7,000 insects by their parents in the course of a single day. 
Behavior : Like its swallow relatives, the bank swallow is highly social, spending most of its time flying in flocks and keeping in touch by constant twittering. If one bird senses danger, it alerts the rest of the flock by making a short, sharp “brrit” sound. Most bank swallows migrate south in the fall when colder weather kills off many flying insects. Flocks follow the same route every year, flying by day and roosting together at night. When the bank swallow returns north in spring, the older and more experienced birds arrive 3 weeks ahead of young birds making the journey for the first time, the males returning before the females. 
Breeding : Since male bank swallows return to breeding grounds before females, they take up residence in old nesting burrows or begin to dig new ones. The male digs about 12" of a new tunnel, then tries to attract a female by singing and flying with fast wing beats at the entrance. If he’s successful, the pair mates and the birds finish the tunnel together. The 4–6 eggs hatch in 14 days; the young are featherless and blind. For the first few days, one of the parents cares for them almost continuously.Young develop quickly and by 14 days can scramble to the entrance of the tunnel to defecate. At 4–5 weeks old, the young swallows are ready to leave the nest and fend for themselves. Early-nesting adults may rear a second clutch of eggs. 

Bill : The bill is short, but has a wide gape to scoop up insects. 
Wings : Swept-back, long and streamlined wings give the bird superb aerobatic skills. In flight, the bank swallow swoops and dips less frequently than other swallows. 
Feet : Long, narrow toes act as hooks to grip vertical banks where the swallow nests. They’re also used as digging tools for tunneling into soft, sandy soil. 
Tail : Forked tail is used as a rudder for executing tight turns at speed. Feathers are spread out when landing, acting as an airbrake to reduce speed.

Weight : 0.4–0.5 oz. 
Length : 4.5-5"
Wingspan : 8"
Sexual Maturity : 1 year
Breeding Season : May–July 

In periods of high winds or prolonged heavy rain, the bank swallow faces lean times, as few insects can take to the wing. However, it’s capable of surviving up to 21 days on its fat reserves alone.

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