Tuesday, September 07, 2004

By Mary Gales Askren
Capital Journal

A pair of binoculars or a spotting scope would have enabled individuals in the Pierre area to watch a pair of bald eagles fledge two eaglets this year, according to wildlife biologists with the state Department of Game, Fish and Parks.

“It’s amazing because the nest is huge, but – it’s quite deep – when the young lay down in there, it’s hard to see them. And then you’ll see them popping their little heads up,” said Carol Aron, who is involved in monitoring bald eagles in South Dakota.

The pair nested in a dead cottonwood tree which was observable from the top of De Grey hill east of Pierre on S.D. Highway 34. By early July, the young eagles were ready to leave the nest.

“They sort of hang out in that area another few weeks. The parents will continue to feed them and they’ll fly. They won’t necessarily go back to the actual nest, but they’ll stay in trees right nearby for several weeks,” Aron said.

For the first time this year, bald eagle populations are being monitored in South Dakota by locating and monitoring nests, she said. The project is a collaborative effort among GF&P, the U.S. Fish and Wildlife Service, and the National Park Service.

As a result of this effort, six new nests were located in the state this year. Aron said other nests exist which have not been located.

“There’s at least a couple on the Cheyenne River, where we saw newly fledged young this spring, but were unable to locate the nests,” she said, in a press release.

As a result of locating and monitoring nests, GF&P was able to confirm that 20 bald eagle pairs fledged a total of 34 eaglets this year. This indicates that many pairs raised two young, which is unusual. While bald eagles commonly lay two eggs, often only one eaglet will survive.

“One nest actually fledged three young, which is almost unheard of for bald eagles,” Aron said.

She said this is probably due to a readily available food supply. When food is sparse, a bald eagle pair may not feed both eaglets.

“If there’s not enough food, they’ll feed the one that hatches first, which is bigger, and then the other one will die,” Aron said.

She said that it is “pretty much inevitable” that the pair of bald eagles which successfully nested near De Grey will return. A pair is usually faithful to a site if they have been successful. If they have a secondary nest, it will be in the same area, according to Aron.

Another bald eagle nest has also been located on La Framboise Island. That nest was abandoned this year, but Aron believes a pair may successfully nest there in the future despite the amount of traffic in the area.

“There are nests in Florida that are literally in people’s backyards that are successful, so they’re not as sensitive as we used to think they are,” she said.

For those who want to watch a pair of bald eagles raise their young next year, Aron recommends beginning to keep an eye on the nest in March or April.

“About April, they’d start working on the nest, adding twigs to it and grass and so forth. They build on to it every year,” she said.

By April, some bald eagles may be sitting on their eggs, which hatch in approximately 34 days. This year, the eggs hatched in early May. The eaglets then remain in the nest between nine and 14 weeks.

“A lot of times the parents will be right near the nest, especially when they’re young. If it’s hot, they’ll be keeping them cool by shading them or keeping them warm, and they’ll be coming in with food. You can actually see them feeding the young,” Aron said.

The nest near De Grey hill is an especially good one to watch with binoculars or a spotting scope, she said, because the historical marker is far enough from the nest so the eagles are not disturbed and it is above the nest, so the viewer can see into the nest.

By the time the young fledge, they are nearly the size of an adult bald eagle, but are not self-sufficient.

“They start to fly and they’re not very good at flying and they’re not very good at foraging, at killing stuff or finding food to eat, so the parents will keep feeding them for a few weeks,” Aron said.

It will be five or six years before the young bald eagles have the white head and tail that mark the mature bald eagle. They can still be identified by their size and by the shape of their bill.

A combination of young and mature bald eagles can be seen near the Oahe Dam during the winter months, Aron said.

Because migration habits of the eagles seen in the Pierre area have not been studied, biologists do not know whether the eagles which nested this spring also winter in the area. A banding study would be needed to determine that, Aron said. At present, one is not planned.

Bald eagles are currently on the federal endangered species list as a threatened species, but the U.S. Fish and Wildlife Service is expected to remove them from the list.

However, GF&P will continue to monitor the raptors to better understand the population. Aron asks that anyone who locates a nest contact her at 605-773-2745.

“Winter is often the best time to find nests,” she said. “Leaves are off the trees and the large nests stand out against the sky.”