Saturday, 2 February 2013

Black Crowned Night Heron


order : Ciconiiformes      Genus & Species : Ardeidae     Family : Nycticorax nycticorax

Although the black-crowned night heron may have to wait its turn while other, larger, species of heron feed, it is a successful and wide-ranging bird due to its flexible habits. The black-crowned night heron feeds mainly at dawn and dusk, but also fishes during the day when it has nestlings to feed. They found in many parts of the world, including Europe, Asia, Africa, North and South America; also found on oceanic islands, such as Hawaii. 

Habitat : The night heron needs dense cover in which to spend the day and build its nest, as well as access to fresh- or saltwater feeding grounds. The heron nests and roosts in oak, pine, willow and mangrove trees. Where there are no trees, it makes do with reeds, bamboo or any bushy vegetation. It feeds near lakes and ponds, rivers and streams, swamps and marshes and sometimes also drier grasslands. The heron favors warm temperate or subtropical areas, but is also found in cooler climates, such as those found in Canada, southern South America and the Falkland Islands in the South Atlantic. 
Food & Hunting : The night heron preys mainly on frogs, fish and insects, but also eats small mammals, young birds, flies, dragonflies, spiders, mollusks and worms.The heron generally stands statue-still on a waterside perch, waiting for prey to come past, but may also walk through water, hoping to disturb an animal. It also hovers, then dives into the water to catch a choice item. 
Behavior : The night heron is most active at dawn and dusk. During the day, it often faces competition at its feeding grounds from other species of heron, which are larger, with longer legs and necks, giving them an advantage in finding food. This is probably why the blackcrowned species feeds mainly when it’s dark and the other species have returned to their roosts. When there aren’t competing heron species nearby, however, the black-crowned night heron commonly feeds by day. At the height of breeding season, when young are hungriest, the heron may hunt at regular intervals throughout both day and night. The black-crowned night heron has a fascinating range of ritualized displays, usually a part of courtship and breeding, in which an adult bird may offer a twig to its partner, wave its head, neck or wings and erect its feathers and head plumes. It also performs an elegant, hopping “ballet.” Outside the breeding season, the heron migrates to warmer regions in winter, where it tends to be more solitary. It’s quieter when not breeding and often goes unnoticed when it is roosting. 
Breeding : The night heron breeds in colonies of from 20 to several thousand birds, in trees or among reeds, on cliff ledges, even open ground. Colonies resound with croaks and barks of young and adult herons. The male starts building the nest, but the female completes it with twigs and other material brought by the male. Nests are spaced so birds are out of beak range of each other. In a season, the female lays one clutch (three to five eggs), but may lay a second. The young hatch in two-day intervals. At first, adults pass food directly into each chick’s mouth, but after a few days just drop it into the nest. After six or seven weeks, the offspring are ready to leave the nest. 

Eyes : Large eyes let the heron spot its prey even underwater at dusk. 
Head : Black cap on its head distinguishes the adult black from its yellowcrowned relative. 
Plumes : Adult has two or three white, ribbonlike head plumes during the breeding season.The bird erects them in courtship displays. 
Legs & Feet : Legs and feet are green for most of the year but turn red or yellow in the breeding season.Toes give the heron a good grip on reeds and similar perches at the riverside. 

Weight : About 1.5 lbs. 
Length : 22-26"
Wingspan : 41-44"
Sexual Maturity : 2-3 years
Breeding Season : Varies with location

Herons have special feathers whose tips crumble into a powder. They spread this over their plumage to keep it water repellent and to absorb greasy deposits.