Bald Eagles

Eagles on the Wabash

Most birds use bits of grass and a few feathers with maybe some small twigs woven in to build their nests to lay their eggs and raise their young. Most species use the nest just one season. After they're abandoned in the fall, they blow away or disintegrate during winter's storms.

But not eagles.

They build for the long term, stacking up what, by comparison to other birds' building materials, are logs for the basic building blocks.

"I've seen'em flying, carrying sticks this big around," said Mike Wathen, joining his thumb and forefinger to form a circle more than an inch in diameter.

Wathen, who lives in southwestern Gibson County, was describing the nest built this year by a pair of bald eagles on the Wabash River near the Gibson-Posey county line.

Wedged high in a cottonwood tree, the nest is now home to an eaglet, which the protective parents are feeding. As they approach the nest with fish or other food, the young bird, which will likely be able to fly from the nest in just a few more weeks, pokes its head above the rim in anticipation of a meal.

Unlike its parents, the eaglet's head isn't white. Only mature bald eagles have white heads, and they usually don't develop their trademark plumage until they're four to five years old. (Bald is a corruption of the Old English word "balde" which means white.)

The nest is near one that was destroyed by a storm last year, Wathen said. The eagles moved just a short distance before rebuilding.

John Castrale, a nongame-bird biologist with the Indiana Division of Fish & Wildlife, is familiar with the site, as he is with most of the 78 active eagle nests in Indiana this year.

Castrale, whose office is in Mitchell, Ind., said he remembered flying over this site last year and observing a nest had come down, probably from the loss of a supporting tree branch.

"It's quite common for a branch or the whole tree to come down in a storm or high water. They construct one of the largest nests of any bird in the world, and every year we see several nests come down in high winds," he said.

The biologist said the lower Wabash, with its meanderings that promote riverside growth that provides habitat for a variety of birds and animals, is an attractive area for eagles to both winter and nest.

"I'm aware of at least three eagles (pairs) in Posey County and another three in Gibson County," he said.

"They continue all the way up the Wabash."

This pair, Castrale said, had built at least three nests in the area. Mating for life, they return to the same area year after year.

Eagles often start building their nests in the late fall and early winter and then wait until near the breeding season in February to finish construction.

"They build kind of a sloppy nest," he said.

Most often they lay two or three eggs that require 32 to 35 days to hatch.

The fledglings are then in the nest for about 12 weeks before they make a first flight.

Their diet consists mostly of fish, with the male bringing a whole one to the nest and the female tearing it into small pieces for the young birds to consume.

Once down to only a handful and on the federal endangered species list, bald eagles have staged a remarkable comeback over the past 20 years with assistance from a cleaner environment and restoration efforts by federal and state wildlife agencies.

The first pair to nest successfully in Indiana since the 1800s was observed in 1991 at Lake Monroe. As numbers have increased, the bald eagle has been taken off the endangered species list and will likely lose its threatened status this year, Castrale said, although in Indiana it will remain a "species of special concern."

The big birds, which can have a wingspan of 6 or 7 feet, have proven adept at adapting to a variety of environments.

"There are some in the city limits of Indianapolis and Terre Haute and on some smaller lakes where we didn't think they'd adapt," Castrale said. Although the number of the birds is increasing, the biologist said people shouldn't get too close so they won't abandon the nest.

"You don't want to go any closer than when the birds react," he said. "If they flush off the nest, you've gone too close. Each pair is a little bit different (in how well it tolerates intrusions)."