The Bald Eagle
By Lowell Tesky
The bald eagle population on the Flowage continued its growth in 1998, reaching 19 nesting pairs Ð one of the densest populations in the state. This is up from 10 nesting pairs only five years ago and speaks well of the habitat quality on the Flowage. Nesting eagles in Wisconsin are surveyed by the DNR from small planes. A mid-April flight determines which nests are active and have incubating birds. A second flight in mid-June counts the number of young eagles in the nests. This year on the Flowage 14 pair successfully raised a total of 27 young, which was close to the Wisconsin average of 75% nest success and 1.25 young per active nest. One nest, in particular, was above average Ð producing four young. This had never been documented in Wisconsin. DNR researchers banded the young June 1 and blood samples were taken for DNA analysis to determine if all four were from the same two parents. (These samples have not yet been tested.) Normally, 40-45% of successful nests have one young, 40-45% have two young, and 10-15% raise three young.
Persons wishing to observe eagles on the Flowage should be able to do so on either the west half or the east half as nests are about equally divided. Care must be taken not to disturb the birds by approaching nests too closely, especially in April and May when a short absence by the adults may be fatal to incubating eggs or young chicks. Usually eagles can best be observed from a boat Ð something they are accustomed to and that seldom disturbs them. In most years, these eagles move south to rivers in southern Wisconsin that stay open all winter or move farther south if cold weather ices over waters they use for fishing. They often return to their nesting territories in February with the first signs of thawing.
Anyone observing a new eagle nest or nest they think is not being surveyed can report its location to Lowell Tesky at the Hayward DNR Ranger Station (715) 634-2688. Also, any sick or injured eagles should be reported; sometimes these birds can be rescued, treated, and released back to their wild home – the Chippewa Flowage.
