Bald Eagle -Eryr Moel
Order Falconiformes
Genus Haliaeetus- fish/sea eagle
Bald eagles, Haliaeetus leucocephalus are large, diurnal, North American birds of prey belonging to the fish eagle family. Easily recognized by its dark brown plumage and white head and tail and yellow beak and feet, though they only gain this plumage at around 4-5 years old. Unpaired individuals will possess brown streaks on their white head up until they form a pair bond, then they gain the complete white feathering. Bald eagles thrive near water feeding mostly on fish, and acting as opportunistic hunters and scavengers, they are also known to steal food from other birds and animals. this is known as kleptoparasitism. They are known to live 30 years or longer in the wild, 38 being the wild record of longevity. They can live up to 50 years. Adults range from 28inches to 38 inches long with a 6 to 8 ft wingspan, juveniles for the first couple of years wander, post breeding dispersal, to seek territories of their own, and in doing so, their wingspans are longer than the adults to compensate for this. they weigh 6 to 14 pounds with females considerably larger. this is known as sexual dimorphism.
Bald eagles mate for life, building huge nests, the largest record, made up of 400 sticks, being 6 – 8ft wide, and up to a depth of 13ft, and weighing 1 metric ton. adding nesting material to them over many years. they hold the record for the largest tree nests of any animal.
Their name origin Bald comes from an old English word balde, meaning white headed.
Bald eagles are partially migratory in some locations, migration takes place during the daylight hours, between 8am and 6pm, where they can take upon thermals and updrafts.
Did you know bald eagles can swim, using their wings to row across bodies of water to the shore, and they also engage in dramatic mating rituals where they lock talons, tumble and spin cartwheels in midair, separating just before they hit the ground. Territories are defended by a mature pair up to 2km of water habitat. they are powerful flyers despite being morphologically less well adapted to the fast flight of golden eagles, the bald eagle is considered much more maneuverable in flight.
Bald eagles represent freedom and strength due to their large wingspan and majestic appearance, they are also very playful, passing various objects between each other mid air has been observed.
Bald eagles have excellent 20.5 vision, and can spot movement up to 2 miles away. they have to focal spots to each eye, being able to focus both forward and sideways at the same time, and have deep fovea, to be able to judge refraction of fish in the water. Diurnal birds of prey in the Accipitridae have excellent 4 way colour spectrum, possessing up to a million cone cells per sq. inch, where as humans we only have 250,000 and bald eagles possess medium UV eye transmitting media. they are very vocal, thus having excellent hearing ability too.
Did you know the bald eagle forms a species pair with the white tailed eagle by occupying the same niche, identical ecological equivalents as in the Palearctic region in the east. Its range includes most of Canada and Alaska, all of the contiguous United states ( here they are smaller), and also Northern Mexico, where they have been noted, in the Sonora, to nest on top of Hecho cactus. This cactus towers over its organ pipe neighbour.
On rare occasions bald eagles are known to adopt other raptor fledglings into their nests observed in 2017 when a pair of bald eagles adapted a red tailed hawk in Shoal Harbour bird sanctuary near Sidney, British Columbia. the named hawk Spunky successfully fledged.
This species was first protected in the U.S and Canada by the 1918 migratory bird treaty which was later extended to all of north America. once a common sight in much of the continent, bald eagles where severely affected in the mid 20th century by a variety of factors such as egg shell thinning due to DDT pesticide poisoning, and bio magnification, making the eagles unable to produce healthy eggs and even making the birds sterile, the eggs were too brittle, due to interference of calcium metabolism, to withstand the brooding weight of the adult. It is estimated that during the 18th century there was around 300,000 pairs bald eagles, but by the 1950s there only remained 412 nesting pairs in the 48 states of the U.S. Also in the 1930s, and with the eagles being innocent of many crimes and long held beliefs, 70,000 bald eagles were shot in a territory of Alaska, in a period of 12 years.
The bald eagle was declared an endangered species in 1967, amendments to the 1940 bald and golden eagle protection act between 1962 and 1972 increased penalties, the most significant in this species recovery, in 1972, DDT was banned, and completely banned in Canada in 1989.. from here on the bald eagle population rebounded, and by 1992 the estimated population rose to 115,000. the most recent data submitted by individual states, 2006 where 9789 pairs where reported.
The bald eagle, is a successful conservation story, and is very much a sacred bird in some North American cultures, and are considered powerful spiritual messengers between gods and humans. The bald eagle is the National symbol of the United states, and adopted as an emblem in 1782. this was a species on the brink of extinction.
did you know bald eagles can soar over 10,000ft high., can stoop down at around 100mph, and glide effortlessly just above water.
SUPER FACT
EVOLUTIONARY ORIGINS
the first eagles, including the ancestors of the sea eagles, like the bald eagle, appeared roughly 36mya, from kite like ancestors, they evolved specialised features for a fishing lifesyle, such as spicules, which are small projections on their feet for grasping fish, and a sharp hooked beak to deal with frozen fish.