2005-08-13 / Columnists

Golden Eagle Sighted on Mackinac Island Bluff

Nature Notes By
Patricia Martin


Patricia Martin

A few mornings ago I received a phone call from a very excited friend. He said that he was making coffee in his cottage when he heard a racket outside. Both the gulls and the crows were shrieking and cawing. He thought that perhaps they were mobbing an intruder and went out with his binoculars to see what he could find. In a large birch on the bluff was a huge dark shape. As he lifted his binoculars, the bird flew out of the tree, bending the branches. It was an eagle. Looking at it from about 25 feet away, he clearly saw golden patches along its head. No white head or white rump patch as in the adult Bald Eagle, nor was it an immature Bald. It was a Golden Eagle. As it flew off on heavily beating wings, the gulls and the crows followed, cawing and shrieking.

GoldenEagle
GoldenEagle I’ve seen Golden Eagles passing over the Island during the spring migration, but it’s fascinating to find them this time of year, though it may be an early fall migrator and as such it may hang around for a few days.

Golden Eagles are usually considered a bird of the western United States and Canada. In one of my bird guides, they’re called a “rare bird of remote mountains, tundra, grasslands, and deserts.” Depending on the bird book you’re using, they tend to breed in northwestern Canada and Alaska (some indicate northeastern Canada as well) and western U.S., where they may spend the whole year. They’re reported to winter in the western U.S. down into Mexico, though one book indicated they may be found during the winter in the eastern U.S. Mackinac is indicated to be on the migratory route in some of the books.

Both the adult and the immature Golden Eagles have rich dark brown body plumage. Along the neck and crown of the adult are tawny golden feathers. The legs are feathered to the toes. The juvenile has a broad white tail band and white wing patches. They have a wingspan of six to eight feet, much like the Bald Eagle, but only weighing about thre and a half pounds compared to the Bald Eagle’s nine pounds. The female is considerably larger than the male. These are actually silent birds, but around the nest they make a yelping bark, “keya,” and some whistling notes. During their soaring courtship flight, they yelp or mew.

These are monogamous birds who pair up for life. They build their nests in cliffs or in trees. These nests are made of sticks interwoven with brush and leaves and lined with fine material. They will sometimes use aromatic leaves in the nest to deter insect pests. Golden Eagles often build two or three nests and use them alternately year after year and their nests may become quite large. After breeding, the female produces two eggs that are about three inches long and are white or cream with brown marks, though one of the eggs is usually unmarked. Both parents incubate the eggs (though the female spends more time than the male and the male will only do it during the day) and the eggs take up to a month and a half to hatch. The male feeds the female during incubation. The eggs do not usually hatch at the same time and the larger bird often kills the smaller sibling. It takes two and a half months for the young to be fledged and the father rarely feeds the young directly.

The Golden Eagle eats a variety of small mammals, including their favorite, Jack Rabbit. They like ground squirrels, marmot, grouse, and ptarmigan. They’ve been known to take down full-grown deer and antelopes and to go after birds as large as a FGreat Horned Owl. In addition, they eat reptiles (including turtles), insects, and even carrion if live food is scarce.

They soar at high altitude in search of prey on what is known as “high patrol.” They then swoop down on their dinner. Golden Eagles have been clocked in a steep glide at 120 miles per hour and it is estimated that they may reach speeds of 150 miles per hour when swooping down on prey during a dive. Their flight pattern alternates deep, slow, powerful wing beats with glides. They like to set their wings and ride upward on thermals, spiraling up to dizzying heights, similar to other hawks and eagles.

The population of Golden Eagles has had its ups and downs. At the moment these birds are considered rare in the east, but are fairly common in the west. They’re a circumpolar bird. In 1962 these birds were put on the protected species list at a time when more than 20,000 of them had been killed in the previous 10 years by sheep ranchers who thought, with little evidence, they were destroying stock. In addition, populations were impacted by DDT thinning the shells of their eggs. In 1964 there were estimated to be only 4,000 to 5,000 pairs of these birds. The population now appears to be stabilized and is increasing. These birds are still in danger from power line electrocution, poison intended for coyotes, and collisions with aircraft.

Keep your eyes open for these birds and if you spot them, please let me know.

Trish Martin is a year-around resident of Mackinac Island, has earned a master’s degree in botany from Central Michigan University, and owns Bogan Lane Inn.

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