Eagle Behaviors - Captive and Rehabilitated Eagles

The term captive bald eagle refers to a bird that cannot be released into the wild to fend for itself, or to a bird that must be released when first capable of surviving in the wild. A bird must be confined to a safe haven when it has received irreparable injuries or has imprinted on humans and will no longer be able to live in the wild. Irreparable injuries such as the loss of a leg or wing often occur when a bald eagle has been caught in a leg trap or shot. In such a case, the bird will never be free to fly in the wild again.

A bald eagle that has been raised by humans may also be damaged. If the eagle comes to associate humans with food and/or has imprinted on a human, the eagle will attempt to approach humans for food. This situation poses a grave danger for humans as well as the eagle. Special care must be taken not to expose bald eagles to human activity (sight, sounds, touch, scent) during a critical period from 9 days to 6 weeks of age. If for some reason the eagle becomes imprinted on a human, the eagle will identify more with humans than with other eagles. This results in an inability to hunt and fend for itself in the wild and also in difficulties mating with other bald eagles.

In these two situations, an eagle may be cared for by concerned people or organizations such as the American Eagle Foundation or a Raptor Center. Imprinted bald eagles may be trained to perform in educational shows such as those conducted by the AEF. Permanently disabled bald eagles will retain their wild characteristics and are usually not suitable for such activities.

Captive eagles may be allowed to mate and raise their own young, depending on the extent of their disabilities. In such a case, when the juvenile eagle is old enough to fledge, it will be released at a site where the bald eagle population is low. Or, a captive eagle pair may be used as foster parents for bald eagle eggs "borrowed" from the wild. Some captive eagles may even undergo artificial insemination to produce bald eagle eggs that the eagle pair will raise in captivity until the juvenile is fledged.

The process of releasing a juvenile bald eagle from a particular site in the hopes that it will return to the site to nest upon reaching sexual maturity is called hacking. "Hacking" is a term borrowed from the sport of falconry. In falconry, the bird is encouraged to return to a raised wooden board containing food. The board is called a "hack." The process of releasing birds of flying age from a site in order to repopulate an area is called hacking.

The hacking process begins when the eaglet is about 6 to 8 weeks of age. At that time the young eaglet is transported from its captive-breeding parents or from an area where bald eagles are relatively abundant (e.g., Alaska, Wisconsin, Minnesota, etc.) to a hacking site in an area where the bald eagle population is low. The site is located in a natural habitat suitable for bald eagles.

From the time the young bald eagle reaches the hacking site until it takes its first flight, the eagle must not be aware of the humans responsible for its care. Typically a hacking tower has been built high off the ground in sight of the young eagle's food source (a large body of water) and suitable nesting, perching, and roosting areas. At least two sides have open bars for the eagles to see out. Humans must take great care not to speak around or be seen by the eagles.

IIn order not to be seen or heard by the eagles, yet still be able to observe the young eagle for its health and safety, special areas are built in the hacking tower which contain a one-way mirror, and feeding and water mechanisms. Observers can sit or stand outside the large wooden cage ( 8' x 8' x 8' minimum dimensions) where the young eagles are kept to record their behaviors. A water pump allows water to enter the cage area without human entry into the cage. Likewise, a special drawer on rollers that prevents the young eagles from detecting the food source can be sent into the cage with food.

In the middle of the cage, a lifelike nest is constructed and lined with soft material, much like an eagle's nest in the wild. While in the hacking tower the young eagles (usually only two or three occupy the same cage) practice wing flapping and other exercises to prepare for their first flight.

At about 12 weeks of age, depending on wind conditions and the young eagle's apparent readiness, one side of the cage is released and the juvenile eagles are free to take their first flight or to fledge. Typically, it takes the young eaglet anywhere from 15 to 45 minutes to gather up the courage to take its first flight. To encourage and assist the young eagles, perch poles, or long poles attached to the corners of the hacking cage near the release side, are present for nervous birds.

It is an exciting moment when the juvenile eaglet takes its first awkward flight. The juvenile will return to the hacking site for a few weeks for support and food, but eventually will take off for parts unknown. With luck, the young eaglet will return four or five years later as an adult to build a nest and raise its young.