Bald Eagle Facts
Q&A with Peter Nye in 2000
New York Department of Environmental Conservation

Characteristics

Q. What is the difference between the life of a male and female eagle?

A. A very interesting question! Very little is known about this, or even conclusively about how long bald eagles live in the wild. This depends, of course, on the type of life they live (how difficult it is, or if they run into problems). Some captive eagles have been recorded to live 47 years; many others in the 30-year range. Wild eagles on the other hand, are believed to live 20-30 years, and we have no idea if males live longer than females. Just some speculation on my part, I might guess males live longer, since females live a harder life (biologically), laying eggs, doing the bulk of the incubation and chick-rearing, and having larger/heavier body mass to contend with and feed. From several observations here in NY, they are also the ones that are attacked and displaced when other females want to come in and take over a territory; I've never seen this in males. Further, females seem to be the more aggressive ones when feeding on carrion, making them more vulnerable to injury and life-shortening situations. I think male eagles have it easier!


Life Cycle

Q: Do eagles push their young out of the nest to encourage them to fly?

A: No! The adults may withhold food as the eaglets get near fledging, and encourage them to fly to a nearby perch to get their meal, but that's about it. Usually, no coaxing is necessary and the eaglets are all too anxious to test their wings!

Q. If an eaglet falls, will a parent fly below the nest to catch it and carry it back to the nest?

A: No!


Ecology

Q. Who do Eagles migrate with?

A. Eagles are believed to migrate alone, not in groups as some other birds (and even some raptors do), and not even with their mate necessarily, although as we learn more, that might change. For now, we've found male and female eagles tend to travel separately to (and from?) their breeding areas. This could be adaptive, so if something were to happen along the journey (an accident or just harsh conditions that might make it difficult for a bird to survive), both of the pair wouldn't be lost, since they are travelling separately and at separate times. We tracked one male to his nest in Ontario years ago, and know from that that he travelled alone and arrived their first; his female mate showed up a few days later.

Q. When do Eagles migrate?

A.This depends on where they are going (where they are from) ! They will generally begin migration when certain environmental cues tell them it is time to initiate the breeding cycle and move back toward their nesting areas. Cues such as day-length (amount of daylight) and hormones within the birds likely are at work. Of course, their timing for this move is critical; they mustn't move north until conditions (ie open water and food) will allow them to survive back on their breeding grounds.

Peter E. Nye
New York State Dept. Environmental Conservation
Division of Fish, Wildlife and Marine Resources
Delmar, NY
Spring, 2000