Saturday, 2 February 2013

Bald Eagle


order : Falconiformes      Genus & Species : Accipitridae     Family : Haliaeetus leucocephalus

A commanding presence in North American skies, the bald eagle patrols waterways and coasts, looking for the opportunity to swoop and snatch unwary fish and waterbirds. A powerful bill and specialized feet are essential tools in the armory of this imposing, fish-eating bird of prey. They found in the coastlines and inland waterways of Canada, the U.S. and northwest Mexico; range extends from the Arctic tundra to the subtropic mangroves. 

Habitat : The bald eagle is found in a range of habitats from rugged, Arctic coasts bordered by extensive coniferous forests to inland freshwater lakes and rivers. In southern parts of the U.S., such as Florida, it is quite at home in cypress swamps and mangroves; it even inhabits parts of the dry, hot deserts of the Baja peninsula in northern Mexico. The bald eagle can often be seen sitting near the top of a tall tree at the water’s edge, which provides a good lookout while waiting for fish, or any other prey in the vicinity, to come into view. Inland-nesting eagles migrate southward in winter, and some of these migrant birds spend the non-breeding season in arid, open country far from water. It is in these surroundings that the bald eagle turns its attention to a wider range of prey. 
Food & Feeding : From a prominent perch that overlooks water, the bald eagle scans the surface for fish. Once prey is located, the eagle flies out toward it, dropping down in a shallow glide. At the last moment it throws its feet down and forward to grab the fish just beneath the water. Hooking the fish into the air, the eagle carries it to a perch. In Alaska during the autumn, when salmon swim upstream to spawn and die, bald eagles gather in great numbers to feed on exhausted and dying fish. As many as 2,000 eagles have been counted; some wade through fast-flowing waters for weakened salmon. Although specialized for catching fish, the bald eagle hunts a range of prey (seabirds, waterfowl, mammals and reptiles). In winter, when many birds move south from their breeding grounds, carrion and even scraps become important parts of the eagle’s diet. 
Behavior : As common with most raptors (birds of prey), the female bald eagle is larger than the male (known as reversed sexual dimorphism).The female needs to be large and strong so that she is able to defend herself against aggressive males, especially with young to look after. The size difference between sexes also reduces competition for food, as the female is able to target prey that is too large or strong for the male to cope with. Sometimes the bald eagle turns to piracy. It frequently intimidates and harasses the osprey, an exclusively fish-eating raptor found in a similar range. The ospreys are often forced to surrender their catches. 
Breeding : Depending on the locality, the eagle chooses from a variety of sites for its nest— a tree, on the ground or on a cliff.The same nest is reused for many years and may eventually become huge. One nest in Florida measured 30' across and 20' deep, and weighed about 4,400 lbs. Several pairs may nest in a relatively small area, occupying territories as small as 2,400 yds. The eggs, normally two, are laid several days apart. Incubation begins when the first egg is laid and the chicks hatch at different times. The first chick will be fed by the parents for several days before its sibling hatches and will, therefore, have a significant size and weight advantage over it. Should the parents be unable to bring sufficient food for both chicks, the older chick bullies the younger and weaker one until it dies of starvation.This behavior ensures that in years when food supplies run short, the older chick, at least, can be raised successfully. 

Bill : As with all sea eagles, the bill is large, heavily built and strongly hooked. It’s capable of tearing flesh from tough carrion into small, bite-sized pieces. 
Eyes : The eagle’s ability to see detail at a distance is extraordinary. Its eyesight is 4–8 times sharper than a human’s.The eyes are fixed in their sockets, so the eagle has to turn its whole head to look around. 
Spicules : The soles of the toes are covered by special scales with spiny projections, called spicules.Together with the sharp talons, these help grip slippery fish. 
Body : These bony extensions of the skull overhang the eyes and help protect them from injury when the eagle is catching and handling prey.They also shield the eyes, like sun visors, reducing glare. 

Weight : 6.6–13.9 lbs. 
Length : 30.4-36.4" 
Wingspan : 5.5-8'
Sexual Maturity : 4 years
Breeding Season : October–April in south, April–August in north 

Bald eagles hunt young sea otters by listening for the noises they make while feeding in kelp beds.