One day back in September 2015, I came upon an unusually large, black bird standing at the side of the road. With a few slow beats of its wide, powerful wings, the great bird was soaring overhead. This was my first encounter with a young American bald eagle.
Several pairs of these birds have established themselves around eastern Long Island. Larger in size than a turkey vulture or osprey, bald eagles are easy to spot. During its first year, an eagle is mostly black with some brown. They begin to develop white on the underbelly in their second year. The fully white head and tail and yellow hooked beak are characteristic of older, mature birds. It can take as long as five years for a bald eagle to become fully mature.
Eagles roost and nest in forests near water. Fish is the mainstay of their diet, but they will eat whatever is available, even roadkill. This fits with the behavior of the bird I saw by the side of the road that day. Birds, snakes, and mammals are taken live or as carrion. If food is scarce they can go without for many days with no ill effects.
Bald eagles begin their nest-building activity in late fall to January. A preferred nest site is in the tallest tree around, below the tree crown, where interwoven sticks will be supported by thick branches close to the trunk. A newly mated eagle pair may take two to three months to construct their first nest. Sticks are added year after year and the nests can grow to be massive in size, averaging four to five feet in diameter and two to four feet deep.
Between one and three eggs are laid, and hatching begins 35 days later. The young eaglets are fed by the parents until they learn to fly, or fledge, in 10 to 12 weeks. By their second year, they are wandering far and wide, eventually settling with a mate of their own. They do not return to the nest area where they were raised. The adults leave the nest site also, remaining in the general geographic area but not returning to the nest again until late fall or winter to make repairs and mate again.
The bald eagle population in our area is increasing, with newly mated pairs establishing nests in the last several years. We can look forward to observing bald eagles around Long Island in the years to come, where they will be busy raising young in their eyrie (nest) cradled high in a tall tree.