Our two male Bald Eagles, Orion (jeuvenile, left) and Danebury.

The January 2006 bird-of –the-month is the impressive American Bald Eagle. The scientific name is Halieetus leucocephalus, which is derived from the words halo (sea), aeetos (eagle), leutos (white) and cephalus (head). The ‘bald’ part of the common name is believed to come from old English meaning ‘white’.

This bird was selected as the emblem of the USA in 1782, though this was not without some argument as there were those, like Benjamin Franklin, who believed that the turkey should have been chosen instead! Like most other raptors, these birds were once heavily persecuted, but they are now protected, with even possession of a feather by non-Native Americans carrying a penalty of up to $10,000. Habitat loss and poisoning from pesticides also contributed to a decline in their numbers, which thankfully has now been halted. Their status has been upgraded from ‘Endangered’ to ‘Threatened’.

These large eagles are unique to the North American continent, being found at some time of the year in every state except Hawaii. The largest concentrations are in the coastal areas of the north-western USA and Canada. Indeed, of around 70,000 birds, half live in Alaska and over 20,000 in British Columbia. Whilst they are mostly found near water along coasts, estuaries, rivers and lakes, they can also be seen in waterless open country, steppes and desert. Not all Bald Eagles are migratory. Those living in the far north tend to migrate south in winter when the rivers and lakes freeze over; some other populations, such as those in Florida, are sedentary. Whilst normally solitary, these birds are found together in their hundreds during the migration and can number over a thousand in the winter roosts. Incidentally, a group of soaring eagles is called a ‘kettle’.

Bald Eagle fishing in a lake in Alaska - Photo by Peter Chance

The Bald Eagle, with the female being sometimes 30% larger than the male, can weigh more than 6kgs and have a wingspan of over 2m. They have a dark brown body with the distinctive white head and tail, and yellow eyes, bills and legs. They have around 7000 feathers that in total actually weigh twice as much as their skeleton. As juveniles they are mainly dark brown all over with some lighter brown areas, and they gradually transition to reach the full adult colouring after the fifth moult. It is at this time that they first breed. They build large stick nests, which, with repeated use, can measure up to 2.5m across and 4m deep. The clutch is 2 to 3 eggs, which are incubated for 35 days. The chicks are fledged after 75-80 days, and stay with their parents for a further month. Sometimes the elder chick kills a younger sibling and the parents make no effort to stop this happening. Some 40% of young do not survive their first flight.

They are very powerful predators, but are also scavengers and carrion-eaters. Their preferred diet is fish, alive or dead, but they will also eat birds, especially waterbirds, mammals and reptiles.

Margaret in 1995

They like to hunt from a perch overlooking water from where they can dive and scoop fish from near the surface, and they are able to lift a catch of nearly 2kgs. Sometimes they will attack birds up to the size of a goose on the wing, though only about one attack in eighteen is successful. Often they will pirate food from Ospreys and other raptors. Perhaps they are best known for wading in rivers and catching fish that are migrating to the spawning grounds. Their hunting ability is aided by their incredible eyesight which allows them to spot a moving rabbit a mile away.

Here at the Hawk Conservancy Trust, we are fortunate to have four stunning American Bald Eagles. Starting with the eldest, we have Danebury who is a 14 year-old male who has been with us since 1993 having come from the Welsh Mountain Zoo. He is the most experienced flier and taught Cheyenne, a ten year-old female, all that she needed to know about display flying. She was bred here at the Conservancy, being the result of a union between Margaret and Larry One-Wing. Larry, being disabled, had difficulty in mating, as he really needed both his wings to balance on Margaret. He overcame this disability by persuading Margaret to move over to the side of the aviary, where he could prop himself up against the wire. Cheyenne and Danebury have been thrilling the crowds at our daily Valley of the Eagles displays. Currently we are training two relative newcomers. Vega, who is now six and in breeding condition, came from a private collection four years ago. At one stage it was hoped that she might breed with our youngest Bald Eagle, Orion, when he reached maturity. He is four and came here when he was six months old. However, she seems rather too dominant and it looks unlikely that they will forge a partnership for the time being. After training, both Vega and Orion should be able to join the Valley of the Eagles display and this will allow us to fly up to four eagles at a time; a spectacle not to be missed!