BALD EAGLE
HALIAEETUS LEUCOCEPHALUS
The Brandywine Zoo has two female Bald Eagles. Saphira, hatched on April 16, 2013, came to the Brandywine Zoo on December 18, 2013. She was blown out of her nest during a tornado and broke her wing, which did not heal properly. This injury left her unable to outstreach her left wing fully. However, she is still able to move around successfully without flying and is otherwise physically and mentally healthy. Granite was hatched sometime between 2006 and 2008. She suffers from lead poisoning, which is increased levels of the heavy metal lead in an animal’s body. Lead interferes with a variety of body and natural processes. Though unfortunately common in eagles and other animals at the top of the food chain, it is unclear what caused her case of poisoning. She is fully-flighted, but lacks the endurance to fly the long distances required for hunting due to her condition and is determined unreleasable because of it. Saphira is larger than Granite, and her left wing does not open or close fully, making her look like one wing “droops.”
HABITAT
Forested areas near bodies of water such as lakes, reservoirs, rivers, marshes, and coast lines.
GEOGRAPHIC REGION AND RANGE
Bald eagles are native to Canada, Mexico, Saint Pierre and Miquelon, and the United States.
DIET
Carnivore – fish and a wide variety of birds, reptiles, amphibians, invertebrates, and mammals. Common prey includes salmon, herring, catfish, shad, crabs, rabbits, and muskrats.
PHYSICAL DESCRIPTION
Mature adult bald eagles have dark brown bodies and wings with distinguishable white heads and tails. Their beaks and legs are a bright yellow. Like many birds of prey, females are larger than males.
SIZE
Length: 3 feet (female); Wingspan: 7 feet for females, 6 feet for males
WEIGHT
Females 10-14 lbs; Males 7-10 lbs
LIFESPAN
Wild: 15-20 years
Under Human Care: 20-30 years
THREATS
Bald eagles were on the Endangered Species list in 1978 due to a dramatic population decline from heavy use of DDT, and hunting. In June 2007, after a spectacular recovery, the bird achieved a status of least concern. Lead poisoning from hunter-shot prey and contaminated watersheds, motor vehicle collisions, and habitat destruction continue to be a threat.
STATUS
Least Concern
REPRODUCTION
• Bald eagles are monogamous and remain together until one dies once they are paired.
• Mating season ranges anywhere from late September to early April.
• The female will lay from one to three eggs and both sexes share the duty of incubation for 35 days
BEHAVIOR
• Diurnal, day active
• Bald eagles can soar, glide, and flap over long distances.
• Bald eagles are capable of floating.
SOCIAL STRUCTURE
• Although these birds are often solitary, they pair bond during the nesting season, and can be found congregating by the hundreds at commercial roosts and feeding particularly in the winter.
• Bald eagles defend their territories during breeding season from a multitude of intruders such as raptors, ravens, coyotes, and foxes.
COMMUNICATION
• They vocalize in grunts, chirps, whistles, and low calls, but are generally a quiet species. One source noted that their exceptional quietness and ability to sneak away from field researchers has been one of the reasons they are so challenging to study in the wild.
• Their throats are almost naked, which makes it easier to scent mark trees using the oils secreted from the gular gland, located on their throats.
FUN FACTS
Bald eagles build the largest nest of all birds. They are up to 4ft deep and 6ft in diameter.
Dichlorodiphenyltrichloroethane, commonly known as DDT, is an insecticide that poisons wildlife and weakens the shell of bald eagle eggs and prevents them from hatching.
The United States declared the bald eagle as the national symbol when the great seal of the US was adopted in 1782.
The bald eagle is the only eagle native to North America.
Bald eagles develop their white head feather when they are 4-5 years old.
They can survive without food for several days. When food is available, bald eagles often gorge and store food in their crop for later digestion.
What are AZA Zoos doing for Bald Eagles?
Bald Eagles are not in a managed breeding program because they are so readily available from wildlife rehabilitators. In fact, US law prevents zoos from exhibiting releasable bald eagles at all. This means every Bald Eagle, in every zoo, aquarium, nature center, or other setting in the US, is a non-releasable individual. Some of these birds may have wing injuries, eye injuries, developmental problems (such as becoming imprinted), or other health issues caused from such as lead poisoning or other things. In giving these non-releasable birds a second chance, they can act as ambassadors for their species and teach the public about the issues they face in the wild.
More images of our Bald Eagles
