Eagles are back

By BILL CHAISSON
I was driving up Interstate 93 from Boston and had just crossed the New Hampshire border when a bald eagle flew fairly low across the highway and settled on a limb of a large dead tree on the far side of the road. Twenty years ago, and perhaps even 10 years ago, I probably would have pulled over to the side of the highway, illegal or not, grabbed my binoculars from the floor behind the front seat, where they always are, and stopped to take in this rare site. This past Monday I just kept on driving albeit with a smile on my face because, you know, eagles are beautiful.

Through much of the 19th and 20th century eagle numbers — we have two species bald and golden, which are not particularly closely related — declined steadily for four reasons. First, their habitat went away. Forests were cleared and wetlands were drained and consequently second, this caused numbers among eagle prey species to decline and took away nesting sites. Third, people straight up shot eagles and other raptors out of the sky because they believed they were preying on their livestock. Finally, DDT thinned the shells of the remaining eagles’s eggs and they failed to hatch.

You can see how one cause built on another. There is at at least anecdotal evidence that golden eagles are strong enough to lift a newborn lamb off the ground and carry it away, so the livestock rationale was not entirely fanciful. But livestock are the only thing on the “range” because the removal of natural habitat and native species, then eagles didn’t have a lot of choice. And DDT poisoning more effectively reduced the size of an already depleted population.

During the 1950s it was estimated that there were 412 breeding pairs of bald eagles in the then-48 United States. The American Eagle Foundation estimates that 300,000 to 500,000 of these birds lived in the U.S. In the 18th century, when it was selected as our national symbol. According to the N.H. Fish and Game, management of the species in this state began in 1980. The first nesting pair returned to the state in 1988, settling at Umbagog Lake in Coos County. They were the only resident birds between 1988 and 1996. Since then new pairs have begun nesting in other parts of the state, with new birds arriving nearly every year. Fish and Game works with New Hampshire Audubon to manage the recovery of these large raptor. Their nests are enormous and quite visible, usually constructed in large dead trees in the middle of a wide open space. Audubon and Fish and Game rope off the area around each nest and monitor activity of both the birds and any visitors.

The funding for this program comes from private donations to Nongame and Endangered Wildlife Program. These donations are matched by the state up to $50,000 annually. The program organizes a count of the state population each November and December, and volunteers are welcomed to help out with this.

Bald eagles are part of subfamily colloquially referred to as “sea eagles.” While Haliaeetus leucocephalus is unique to North America, a very similar species called the white-tailed eagle is found all across northern Eurasia. Other species are found throughout the Old World, with our bald eagle the only one in the New World. As their name suggests, they are strongly associated with water and they eat mostly fish. Studies of bald eagles show that its diet is usually more than half fish over most of its very large range. Twenty-eight percent of their diets consists of other birds (particularly waterfowl), 14 percent mammals and 2 percent other prey. They are also not above scavenging road kill and the kills of other predators, including bullying osprey out of fish they have just caught.

The 1918 Migratory Bird Treaty protected them first, followed by the Bald and Golden Eagle Protection Act in 1940, which made trapping and killing them illegal. DDT was banned in the U.S. In 1972 and in Canada in 1989. They were removed from the endangered species list in 1995.

I first saw a bald eagle in 1983 while traveling in Alaska. I was on my way down to Homer at the southern tip of the Kenai Peninsula and was told to look out for the “Homer pigeons.” This information was provided with a nudge and wink that Alaskans like to give outsiders. When I got below Kenai itself and headed for Homer, I started to see them: dozens of bald eagles sitting on the power lines along the road. By the time I got to the outskirts of Homer, a small fishing village at the western end of continuous roads in North America, I was never out of sight of a bald eagle either sitting on a wire or coasting along the shoreline looking for dead salmon.

Since that time I have seen them more and more regularly in the northeaster U.S., first as wintering birds coming from further north, but by the 1990s as breeders, particularly in upstate New York. In the 2017 breeding season, New Hampshire had 59 territorial pairs. Thirty-eight of them raised a total of 59 young. In that year, the state removed the bald eagle from its list of threatened and endangered species.