Diet and Food Consumption

Bald Eagles feed on a variety of prey items including fish (mostly shallow-water fish like gizzard shad, cisco, suckers and small northern pike), waterfowl, seabirds and small mammals like rabbits. Eagles will also take advantage of roadkill and carrion (dead animals). Scavenging, the most popular feeding strategy, allows eagles to conserve energy in the winter by providing them with food that has taken little effort (fewer calories) to obtain. Juveniles will depend on carrion as a primary source of food until they become more proficient at hunting. 

Adults and chicks will eat the same prey, but adults will tear the prey into bit-sized pieces for their chicks using their sharp beaks. Older nestlings can tear apart whole prey on their own. With significantly larger wing and tail surfaces, juveniles are more efficient at soaring and in turn more effective at locating carrion.

Another way that an eagle will obtain food is by stealing it from another bird, like another eagle or osprey. Many times one eagle will harass another until it is forced to drop the prey in order to defend itself from the others’ talons. The pursuing eagle will then dive at top speed after the prey that was dropped. sometimes catching the dropped prey in mid air. Otherwise, the eagle will retrieve it from the water or the ground where it’s fallen. This chase may look as thought it is by chance, but it isn’t; the dominant will steal from the subordinate and the larger bird will steal from the smaller. Stealing is the second most popular feeding strategy. 

Eagles take much of their food from the surface of the water. Many times eagles will perch on the windward side of the islands or peninsulas allowing the prevailing winds and waves to wash up the dead or dying fish. People have reported seeing eagles take waterfowl right out of the sky, but usually they will harass them until they tire and need to land, making them much easier for the eagle to catch.

There are times when an eagle will follow a diving duck, with talons outstretched, right into and under the water. Some people have seen eagles dig up burrows of petrels, anklets and puffins in order to capture the birds. There have also been reports of eagles crushing and devouring the contents of other birds’ eggs.

Actually catching prey is the least popular eagle feeding strategy. While to some this sounds like laziness, it’s actually a highly developed method of energy conservation. Using the most energy efficient foraging method can mean a longer, less stressful life for an eagle.

Prey Requirements

In order to maintain body weight and have energy to function, an eagle must find food sources with sufficient calories.

Compared to the red meat of mammals (deer, raccoon, skunk and possum) fish are poor food sources; however, fish are more likely to be available. An eagle eating only fish would need to consume from six to eleven percent of its body weight a day (anywhere from one to one and one-half pounds of fish. If it feeds on a higher quality of food, like carrion or small mammals, the eagle needs to consume only about six percent of its body weight each day.

Weather (air temperature) and the amount of energy expended in locating food also affects how much nourishment a bird needs. Under certain conditions, eagles can go without eating for several days. 

Feeding Behaviors

Eagles watch each other for clues about food. Young birds follow the older birds from winter roosts to hunting or scavenging locations, thereby learning the skills necessary to survive.

Eagles use each other to spot prey, or carrion sources, and will very quickly surround carrion discovered by another eagle. This is where their outstanding vision comes into play -- an eagle can spot another eagle soaring from up to two miles away. Other times an eagle may take advantage of other birds like crows or ravens to locate food. 

About a half-hour before sunrise eagles will leave their night roosts and choose hunting perches in their feeding areas. For about an hour after sunrise they fish and feed heavily. Once they’ve eaten their fill, they’ll spend much of the rest of the day perched in trees to conserve energy. They may take flight again if assured of getting food as a reward for their energy expended.