The Bald Eagle – The Great Symbol of North America

The Bald Eagle is a fish eagle and belongs to the genus Haliaeetus = sea eagle. As such, the Bald Eagle is the largest of all fish eagles and it symbolises freedom and power. Little wonder that the Bald Eagle not even is the symobel of North America but also the coat of arms of the US. The Bald Eagle is a very impressive bird. Most remarkeable are the adult bird’s white head, the yellow bill and the white tail.

We know the Bald Eagle from media coverage and actually also from commercials where the eagle sometimes is used to attract viewers attention. Despite the occasional media attention, until 2016 the Bald Eagle, in the US was classified as endangered species.

Conservation

Although the Bald Eagle is still classified as an endangered species, it made a great recovery. Its global breeding population is estimated at about 250,000 individuals. Of that number about 88 per cent spent its time mostly in the US, about 31 per cent mostly live in Canada and up to 8 per cent reside in Mexico. The number of individuals appear to be quite satisfactory, though it is not much compared to the vast continent of North America.

The agent DDT proved deadly to the Bald Eagle leading to an enormous drop in population numbers in the 1960s. In the 1970s DDT was banned as a substance. The Endangered Species Act of 1973 included the Bald Eagle as an endangered species in all US states from 1978. At that time the population of the Bald Eagle was down to 417 breeding pairs. In 2016 the eagle was removed from the endangered species status. The number of Bald Eagles in the US, including Alaska, is estimated at about 143,000 individuals.

More Threats

Current threats are lead ammunition. This might sound strange but in fact Bald Eagles and other raptors take in parts of the lead bullet with their food. Later the lead bullets are enough to kill the eagles and other scavengers.

Another threat that is also a major problem for raptors in Europe are wind energy plants. Although wind energy is an environmently friendly way of producing energy, it proves deadly to raptors.

Heavy metals in general, such as mercury, prove deadly to raptors in the long-term. Raptors are harmed by heavy metals because these birds are the end of the food chain and because this substance accumulates in the body. The same effect comes from pesticides and proved a great danger to eagle populations.

EAZA Ex-situ Programme

In Europe Bald Eagles are kept in zoos and falconries. There Bald Eagles are breed for later release into the wild. This is part of the EAZA EX-situ Programme (EEP), formerly kown as European Endangered Species Programme. This is a population management programme for animals, set up to help endangered species in the wild.

Bald Eagle – Distribution – Movements – Habitat

Distribution: The natural distribution area of the Bald Ealges stretches anlong the US westcoast, beginning in Alaska and down south to Baja in California. Along the eastcoast the eagle distributes from Maine donw to Florida in the south.

The largest populations are found in the northwest of the US, the Alaska southcoast and in Florida. Additional populations are in the east of Alaska and from there stretch in southeast direction down to Ontario, Quebec, Newfoundland and Labrador. There are no populations north of the Hudson Bay area.

Movements: During winter, Bald Eagles migrate from northern areas southwards into the warmer regions of the US. About 2,000 individuals gather at the Canadian Howe Sound between November and February.

Wintering: Bald Eagles winter from Canada southwards to the northern parts of Mexico.

Habitat: The Bald Eagles needs large open bodies of water to find sufficient food. Marshland, lakes, coastal areas and river rich of fish. In order to find suitable sleeping places and breeding places wooded areas with large trees are essential.

Bald Eagle – Behaviour

The Bald Eagle is a diurnal bird, meaning the activity phases are during daylight. Bald Egles are expert gliders using thermals and updrafts. While the Bald Eagle is slower in active flight than the Golden Eagle, it must be said that they are fast gliders.

They are territorial during breeding but are social outside during winter and migration. Hunt from search flight and from perches. Fish is catched out of water by nose-diving into the water. This is similar to the Osprey. After catching a fish, Bald Eagles carry the catch away. Up to 50 per cent of its own weight can be carried by a Bald Eagle in flight.

During nose-dives a Bald Eagle can reach speeds of up to 120-160 km/h. During direct flights speeds of up to 70 km/h can be reached. Bald Eagles glided in altitudes of up to 3,000 metres (= 10,000 feet) max.

Taxonomy

Order: Birds of Prey (Accipitriformes)
Family: Accipitridae
Genus: Sea Eagles / Fish Eagles ( Haliaeetus)
Species: Bald Eagle – Bald Fish Eagle
Scientific Name: Haliaeetus leucocephalus

Names and Synonyms of the Bald Eagle

German Name: Weisskopfseeadler
French Name: Pygargue à tête blanche
Spanish Name: Pigargo Americano
Italian Name: Aquila di mare testabianca
Dutch Name: Amerikaanse Zeearend
Danish Name: Hvidhovedet havørn
Swedish Name: Vithövdad havsörn
Finish Name: Valkopäämerikotka
Norwegian Name: Hvithodehavørn
Russian Name: Белоголовый орлан

Breeding

Mature: Bald Eagles become mature between 3-4 year.
Mating Season: Mating takes place directly after arriving at the breeding area. However, Bald Eagles are monogamous breeding pairs for live.
Clutches per breeding Season: only one brood
Breeding Period: between March to the end of May

Clutch: 1 clutch per year
Eggs: 1-3 eggs per clutch
Recurrent Clutches: no recorded data available.
Laying Interval: 3-4 days
Begin of incubating: Most probably, incubation begins from after laying the first egg.
Incubation: 33-36 days. Both parents share the task of incubating, but it is mostly the female sitting on the eggs. It is only relieved from duty when the male arrives with fresh prey at the nest.

Hatching: The juveniles hatch according to the laying interval
Fledging: Juveniles are hatched during the first days in nest. Juveniles fledge after 56-98 days. In case of insufficient food supply, it can take up to 98 days for juveniles finally to take off for the first time.
Dependency: After fledging the juveniles are still depending on their parents for several months.

Miscellaneous –
Food – Longevity – Mortality – Threats

Food: The main diet of the Bald Eagle is fish. Prey can also consist of birds, smaller mammals and snakes, but only to supplement the main diet. Bald Eagles prey on waterfowl such as ducks, coot; further on rabbits, rats, tortoises and snakes.

Longevity: In the wild, Bald Eagles can reach 20 years of age. Though, in captivity they can get much older.

Mortality: Only 50% of all juveniles fledged survive the first year. Once a Bald Eagle survived the first year, mortality stands at about 88% per year.

Threats: The Bald Eagle is still endangered by hunting in migration areas. Natural predators are large gulls, raven, magpies, the wolverine, owls, other eagles, lynx, brown bear and, believe it or not, the racoon. The most dangerous threat to Bald Eagles, however, is DDT and this agent’s long-term effects.

Bald Eagle Flight Display

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Please also check out the following link for information on the EAZA programme: https://www.eaza.net/conservation/programmes/