Wild Florida: Bald Eagle

When most people think of Bald Eagles, they think of Alaska or the Pacific Northwest. But the Bald Eagle is a year-round  Florida resident too–in fact we have over 1,100 breeding pairs, one of the highest Eagle populations in any of the lower 48 states.

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When European settlers arrived in North America, there may have been as many as half a million Bald Eagles in the United States. Virtually every large lake or river had its resident nesting pairs.

The Bald Eagle, Haliaeetus leucocephalus, is the largest eagle in North America and the second-largest bird (only the California Condor gets bigger, and the Golden Eagle is about the same size). The Latin name means “white-headed sea eagle”; the common name was originally the Piebald Eagle, referring to the brown and white color pattern. The Bald Eagle’s clostest living relatives are the very similar White Tailed Eagle which inhabits northern Europe and Asia, the Steller’s Sea Eagle in Siberia, and the African Fish Eagle.

In North America there are two recognized subspecies of Bald Eagle. The Southern Bald eagle H. l. leucocephalus is found from northern Mexico through Florida up to Virginia and over to California. The slightly-larger Northern Bald Eagle H. l. washingtoniensis ranges from the northern half of the US through Canada up to Alaska. Much of the northern population is concentrated in Alaska and the Pacific Northwest, where salmon runs provide ready food sources, and in the Great Lakes area; much of the southern population is found in Florida.

Because the Bald Eagle is the symbol of the United States, everyone recognizes it even if they have never seen one. Eagles are 3 to 3.5 feet tall, with wingspans reaching almost 8 feet. The adults have the familiar white head and tail; subadults are mottled brown. It takes about 5 years for youngsters to get their adult colors. The adults weigh around 8-10 pounds, with females noticeably larger than males. Despite their size and regal appearance, Bald Eagles have a very un-regal weak chirping call, similar to an Osprey. (The piercing screams that you hear in TV commercials are usually dubbed-in Red-Tailed Hawk calls.)

To provide sufficient food for their growing chicks, Bald Eagles usually nest near water. The northern subspecies is migratory, while the southerns are year-round residents. The birds mate for life and return to the same spot each year, and over time the nest can become immense, over a ton of interwoven branches and sticks. Eagles nest much earlier than most other birds; it’s not unusual to see Bald Eagles incubating their eggs (the male and female take turns) with snow still piled up in the nest. In Florida, where food is plentiful year-round, nesting can happen at any time of the year, though most eggs are laid in spring. Each nest usually contains two eggs, though normally only the strongest chick will survive. The young leave the nest at about three months and become independent at about six months. Banding studies have shown that most of the subadults raised in Florida depart the state and settle down further north, as far away as the Chesapeake Bay. Adult Bald Eagles have no natural predators, and live for about 20 years in the wild.

Although Bald Eagles are opportunistic hunters and can take prey as large as young deer fawns, their primary food is fish, and they are seldom found far from water (small waterbirds like ducks and grebes are often on the menu as well). Eagles will also readily scavenge carrion, and will often obtain meals by bullying other birds (especially Ospreys) into surrendering fish that they have caught. Benjamin Franklin considered the Bald Eagle’s behavior to be dishonorable, and argued that the more stately Wild Turkey should be the nation’s symbol instead.

By the time the US gained independence in 1783, however, the Bald Eagle was already in trouble, with fewer than 75,000 birds remaining. Habitat was lost as humans built more and more settlements. Eagles were viewed as competitors for fish (especially in salmon areas), and were also considered as threats to agriculture, it being believed that the birds would kill lambs and other farm animals (and perhaps even small children). The Bald Eagle was systematically shot and poisoned. By the mid-1800’s, ornithologist James Audubon was already concerned about the Eagle’s future.

The most crippling blow came in the 1940’s and 1950’s, with the widespread use of the insecticide DDT to kill mosquitoes. The pesticide runoff contaminated the fish with DDT which then passed on when the Eagles ate the fish; the chemical caused the eggshells to become unusually thin and break while the birds incubated them. For a period of over a decade, virtually no new young Eagles were being produced. The Bald Eagle population plummeted, with remnant populations surviving only in Alaska, eastern Canada, and Florida. At this time, there were only 400 confirmed nesting pairs of Eagles in the entire continental United States.

In 1972, DDT was banned in the US, and in 1976 the Bald Eagle was placed on the Federal Endangered Species List. The birds began to recover, and slowly spread back into their historic ranges. By 1996 the Bald Eagle’s status was upgraded from “Endangered” to “Threatened”, and in 2007 it was removed from the Endangered Species list, though eagles are still protected by state and Federal laws. Today there are confirmed nesting Bald Eagles in every state (except Hawaii). It is estimated that there are now over 1,100 breeding pairs of Bald Eagles in Florida.

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One thought on “Wild Florida: Bald Eagle”

  1. I have always wondered where the bald eagle got its common name from, and whether it is related to African fish eagles. Now I know. 🙂

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Forgotten mysteries, oddities and unknown stories from history, nature and science.