Saturday, 2 February 2013

Black Headed Gull


order : Charadriiformes      Genus & Species : Laridae     Family : Larus ridibundus

The black-headed gull thrives close to humans, as it has learned to exploit the rich feeding provided by agricultural land, dumps and hand-outs in city-center parks. The black-headed gull has a multipurpose body plan. Agile in the air, it’s also nimble on the ground and yet quite at home paddling on the water. They found across Europe and Asia, from Iceland to Russia; some move south in winter to the Middle East, western Africa and eastern North America. 

Habitat : Adaptability is key to the success of the black-headed gull, and the only major habitats that it can’t exploit at some stage in the year are forests and mountainous areas. Breeding colonies are located on flat lowland areas or upland plateaus near calm and shallow freshwater, such as lakes, reservoirs, gravel pits or slow-moving rivers. It also breeds on both fresh- and saltwater marshes and in reedbeds, as well as on drier sites, from sand dunes to moorland. Outside the breeding season, the gull flies long distances in search of food. In the north, it moves south in winter. Other populations don’t disperse so far, traveling to sheltered coastal estuaries and man-made habitats, including refuse dumps, sewage plants, gravel pits, farmland, golf courses, parks and even gardens. 
Food & Feeding : The gull varies its diet and feeding habits according to the season and food availability. It walks in search of food in short vegetation, such as winter wheat or grazed grassland or wades in shallow water. When it spots an invertebrate or a crustacean, the gull scoops it up, sometimes dashing forward to seize its prey. Skilled in the air, the gull often flies just a few feet above fields or water, dipping to snatch prey from the surface. When there is a hatch of flying insects — typically flying ants — in warm weather, flocks of gulls spiral after them on the rising air currents. They also steal food from smaller birds. 
Behavior : The black-headed gull is usually seen in a flock. It appears that families and groups of gulls stay together in flocks of varying size for several years; in fall and spring dispersals, flocks may be several thousand strong. When it roosts at night, the gull is vulnerable to foxes, weasles and other mammals, so it often chooses a safe place on open water (reservoirs and lakes), using islands and sandbanks. It may fly 12 miles to its roost each evening, collecting at an “assembly point” before the flight. The black-headed gull uses a series of ritualized displays to communicate with others and to reduce aggression. For example, the male advertises his possession of a nest site by throwing his head back and calling loudly. 
Breeding : The male and female gulls build their nest together — a simple scrape in the earth to a mound up to 1.5' high in shallow water that keeps the eggs above water level.Two or three eggs are laid at an interval of two days. Both parents care for their downy chicks, which, like the eggs, are well camouflaged until they fledge after five weeks. 

Bill : The pointed bill lets the blackheaded gull catch insects in flight and pick them off the ground or plants. It’s also sturdy enough to deal with carrion and scraps. 
Plumage : In August, the black-headed gull loses its dark “hood.” A faint smudge behind the eye is all that remains until the hood is regained in the following February or March. 
Feet : Scarlet feet are webbed, letting the gull paddle on the water surface and stand on soft mud or sand. 
Juvenile : The juvenile has orangebrown areas on its back, wings, neck and head, pinkish legs and feet, and a black tip to its pale bill. 

Weight : 7–13 oz. 
Length : 1-1.5'
Wingspan : 3-3.3'
Sexual Maturity : 2 years
Breeding Season : April–July 

The scientific name of the black-headed gull means “laughing gull,” referring to its rasping, kreeay, call.