The Carlisle Mosquito Online

Friday, April 2, 2010


(Photos by Gay Campbell)

Bald Eagle

A Bald Eagle in Carlisle is not an extremely rare sight. They are seen on occasion. Claire Wilcox saw one over the Concord River on the downstream side of the Rte. 225 bridge on March 6 and another near Nine Acre Corner on the Sudbury side of Rte. 117 on March 28. Ken Harte has seen one from time to time in Billerica and they occasionally turn up in the Concord Christmas Bird Count. It is much less common to see one repeatedly day after day. Gay Campbell of River Road has had daily visits from a bald eagle for ten consecutive days. “I have observed the eagle sitting on the same tree limb every day now since March 15th, usually for about one to two hours in the morning and again in the early evening. He doesn’t seem particularly bothered by us unless we get too close. The tree he favors is about 50 feet from our living room window, and sits at the edge of our lawn, at the top of the bank overlooking the marsh, which is now flooded and about four hundred feet out to the Concord River. He also favors a tree just a little bit upstream, but it is surrounded by evergreens so he is harder to see there.”

The best vantage points to see if this eagle is still in the neighborhood would be either from the bridge on Rte. 225 or from a canoe or kayak on the river a little upstream from the bridge.

Name: The Bald Eagle is Haliaeetus leucocephalus. The genus name comes from a combination of hal meaning sea and aeetos meaning eagle. The species name is from leuco meaning white and cephalus meaning head and is very descriptive of the bird. The common name dates to a time when bald meant white and had nothing to do with follicular challenges. Skewbald and piebald incorporate the same sense of “bald” to describe horses with white patches.

Description: The Bald Eagle is big (about three feet from tip of beak to tip of tail and with a wingspan of 6 and a half feet or more). The average weight (from Sibley) is nine and a half pounds. Other sources cite weights up to 14 pounds. The more conservative weight is about the same as 15 Pileated Woodpeckers or three Great Horned Owls. If you are not familiar with birds, think of two flying five-pound bags of sugar with a hooked yellow bill and eight talons. The adult Bald Eagle is easily differentiated from other big birds of prey by its white head, white tail and brown body. It soars with flat wings unlike the v-shape of the soaring Turkey Vulture. Juveniles are mostly dark colors and develop adult coloring by age four or five.

Food: Its main food is fish, but it is an opportunistic feeder and eats carrion and road-kill in the winter, as well as small mammals, snakes and large birds, usually waterfowl. It uses its talons both to grab prey and to kill it by puncturing. It uses its beak to rip the food into dinner-size pieces. It is known to steal prey from other birds and mammals. Campbell has already made the following observations: “When we had the ‘big rain’ there were a couple of seagulls around and the eagle chased them away from their fish catch a few times… the birds at the bird-feeder don’t mind him at all, although they do fly up when he soars off. Also not bothered at all are the Canada geese, some ducks, and the beavers.”

Breeding: For the breeding season, the Bald Eagle chooses a forested habitat near a large body of water. There are pairs breeding at the Quabbin Reservoir and at sites on the Merrimack River. It is possible that the Concord River, at its normal levels, could provide a suitable habitat. The recent flooding seemed to some to be of biblical magnitude, but so far only one eagle has been seen at a time. If the flooding had been truly biblical, Noah would have brought us two. If Campbell’s eagle finds a mate here I’ll revise my opinion of the flood.

Status: The Bald Eagle is at the top of the food chain. It is therefore very susceptible to environmental toxins. Forty years of protection under the Endangered Species Act (and a predecessor act) supported by recovery and reintroduction activities have saved the species from possible extinction due to effects from DDT. The Bald Eagles breeding now at Quabbin are a direct result of the introduction of nestlings from Michigan in 1982. From 1982 to 1988, 41 eagle chicks were brought to Quabbin from Manitoba, Nova Scotia, and from Michigan. Protection under “endangered species” was lifted in 2007 but the bird is still protected by other laws which prohibit trade or collection of eagles, their eggs, nests, or parts without a permit.

Symbol: The eagle represents freedom, strength, and such a broad manner of majestic and nationalistic ideals that it is used as a symbol in the coat of arms of at least two dozen countries. But of all the eagles in the world the Bald Eagle is found only in North America. It is the one featured on the Great Seal of the United States.

Poetry: April is National Poetry Month and of the thousands of references to the eagle in poetry I chose an extract from Carl Sandburg’s poem “Wilderness.” (Sandburg’s writing is as singularly American as is the Bald Eagle, and besides, he had white hair and penetrating vision.) “There is an eagle in me and a mockingbird … and the eagle flies among the Rocky Mountains of my dreams and fights among the Sierra crags of what I want … and the mockingbird warbles in the early forenoon before the dew is gone, warbles in the underbrush of my Chattanoogas of hope, gushes over the blue Ozark foothills of my wishes – And I got the eagle and the mockingbird from the wilderness.”

Sources: Cornell Lab of Ornithology at; National Geographic Field Guide to the Birds of North America; The Sibley Guide to Birds, David Allen Sibley;;; Complete Poems, Carl Sandburg.

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