It's nest-building time for bald eagles
Bald eagles are beginning to lay eggs inside their gigantic stick-nests once again all across Minnesota. And these days eagles nest in virtually every corner of the state — from the far northwestern-most counties, up and down the Red River valley, east to Lake Superior, and nearly everywhere south.
Minnesota provides some of the best habitat for nesting bald eagles anywhere. Save for Canada, Alaska, and Florida, nowhere else are there more nesting pairs of bald eagles in North America than in Minnesota.
Other states with robust bald eagle populations include Wisconsin, Michigan, Washington, and Oregon. And though Minnesota stopped surveying eagle nests some time ago, that's a good sign. It's a sign that Minnesota's eagle population, once considered endangered, is very healthy.
The bald eagle is a noble looking raptor. It is no small wonder that this bird was chosen as our national emblem. Its strong features, large size, powerful flight, longevity — not to mention its imposing weaponry — are symbolic to our nation.
Perhaps one of the most startling characteristics of an eagle is its wingspan. Anywhere from six to seven and a half feet from wingtip to wingtip, the bald eagle commands the skies as it soars above the landscape. Weighing around 10 to 14 (males weigh slightly less) and as long as three feet from beak to tail, bald eagles are certainly large enough to capture sizable prey.
Its preferred food, however, is fish. Eagles will readily swoop from a good lookout perch over a lake or river to capture unwary fish. Yet, they are also equally okay with stealing and scavenging for its meals. Bald eagles are adept at stealing fish from ospreys or claiming a carcass from a mob of crows and ravens.
It is also very common to see bald eagles along our roadways feeding on deer carcasses and other carrion. It is for this reason that it's important to slow down when approaching eagles feeding on roadkill. Dozens of Minnesota's eagles are killed every year on our highways.
The white head and white tail feathers of a bald eagle do not become visible until the bird reaches about four or five years old. Juveniles are brown, mottled with white plumage throughout. Many people, therefore, confuse young bald eagles with other species of hawks and eagles. It is often reported that golden eagles have been observed when in fact it was merely a juvenile bald eagle that was seen.
Adult bald eagles form lifelong pair bonds. Able to reach ages of 30 years old in the wild, a mated pair of eagles can raise many offspring over their lifetime. Often returning to the same nest every spring, a pair will continue to add sticks and nest-building materials to their nest year after year.
The size of a bald eagle nest is worth noting. Because the adults add materials to the nest each year, a nest can reach weights of up to two tons and a diameter of up to 10 feet! It takes a strong tree to support such a nest. Nests are usually built in large in trees such as white pines and cottonwoods near lakes and rivers. But where no suitable trees are available, such as Alaska's tundra, the ground or a cliff will suffice.
On a wilderness fishing trip to the Goodnews River in southwest Alaska many years ago, I saw firsthand how bald eagles raise their young in a treeless, tundra environment. After beaching our rafts on shore one afternoon so we could eat lunch, we decided to take a hike and explore. The river's channel was deep, with high, sandy banks rising above us on each side.
Once we were on top of the riverbanks we were greeted with tundra sprawling for miles in all directions, giving us a breathtaking panoramic view of the surrounding mountain range. We also noticed a pair of bald eagles circling overhead, calling in weak and chirping whistles. It was at this time that we noticed a large and conspicuous mound of earth at the edge of the high bank some distance away.
Investigating the strange structure, we soon learned that it was an active bald eagle nest. Cautiously, we approached it just close enough to see a single, half-grown eaglet sitting in the middle of the nest bowl staring as curiously at us as we it. I was thrilled, to say the least.
While it not rare to see bald eagles during the winter here in the Northland, most eagles do migrate where food is more plentiful. Even so, right now throughout much of Minnesota, bald eagles are establishing pair bonds, adding sticks to nests, and beginning the nesting season once again, as we get out and enjoy the great outdoors.
(Check out "Eagle Cam" and watch an active nesting pair of bald eagles located near the Twin Cities: http://www.dnr.state.mn.us/features/webcams/eaglecam/index.html