Despite the noise from speeding motorboats, and intrusive hikers and barking dogs, a pair of bald eagles has made a suburban park along the Milwaukee River home.
"It has been a good hundred years since a bald eagle built a nest in southeastern Wisconsin," said Owen Boyle, Conservation Ecologist for the Department of Natural Resources (DNR) in Milwaukee. The pair of eagles was reported to the DNR on April 28.
How long the eagles will stay will depend, in large part, upon disturbances being kept to a minimum. The birds require isolated living areas, and can be easily disturbed by human activity. "We are not sure how long the bald eagles will stay. If people stay a safe distance away and don't appear to be a threat, they most likely come back next year. We are asking the public to keep a distance of at least 330 feet, about the size of a football field, from the tree containing the nest," said Boyle.
Bald eagles remain an endearing national symbol. Their strikingly contrasting features— white head, dark-brown body, and large yellow hooked beaks—set them apart from other birds. Eagles are also the most protected species in the United States; harming, harassing or possessing a dead eagles' feather is a federal crime. Even the nest tree is protected by law.
Like all migratory birds, bald eagles head south for the winter and come up north to breed in the spring. During the breeding season, mated bald eagles establish and defend their territory. They usually return to the same breeding area each year.
Boyle says that their future in the area hinges on whether the environment is hospitable to their specific needs.
"We are asking everyone to give them a chance to establish a territory. If they are able to do that, they usually return to the same area each year. The eagles will even use the same nest year after year, but make it bigger. This year the pair of eagles did not lay eggs because they were not yet mature enough," said Boyle.
Bald eagles only live in North America. They once inhabited the entire continent wherever there were adequate nest sites and an abundant supply of fish. But the bald eagle population declined drastically during the 1950s when the use of pesticides, like DDT, became common. As they consumed contaminated prey—fish that had accumulated large amounts of poison—it caused them to lay thin-shelled eggs that would break before hatching.
Following the 1972 ban on the use of DDT, the number of nesting pairs of bald eagles and the young they produce in Wisconsin have increased steadily. Wisconsin has the third largest eagle breeding population in the 48 contiguous states. According to Bill Ishmael, DNR wildlife biologist at Spring Green, "Bald eagles are listed by the federal government as a "threatened" species overall in the United States, but within the state, Wisconsin has listed the bald eagle as a "special concern".
The city of Mequon, WI posted a sign on a trail in the town's park that cautions hikers not to disturb the pair of bald eagles. Boyle commented on the support the city has provided in buying the sign and putting it up.
Feeds