If anyone would’ve told lifelong Philadelphia birder Ruth Pfeffer 20 years ago that adult bald eagles would be standing in the creek across from Valley Green Inn, she never would have believed it.
But on the 30th anniversary of a statewide effort by the Pennsylvania Game Commission to re-introduce the majestic bald eagle after the ravages of DDT pesticides, Wissahickon Valley Park visitors are getting rare glimpses of these iconic birds.
Pennsylvania’s adopted eagles
In the early 1970s, the federal government banned the use of pesticides that were devastating the life cycles of birds like eagles, peregrine falcons and ospreys. As a result of the poisons, the birds’ eggshells were too weak to sustain the chicks inside. At the time, the Game Commission could document only three bald eagle nests in the entire state of Pennsylvania, all of them in northwestern Crawford County.
So in 1983, the Game Commission launched a seven-year program that brought eaglets from Saskatchewan, Canada to be specially raised by human volunteers in Pennsylvania and then re-introduced into their former eastern range.
The effort released a total of 88 bald eaglets into the wild. According to the Game Commission’s annual July statement on Pennsylvania’s bald eagles, the state boasted 25 pairs of nesting bald eagles in 1998, and just three years later, that number had doubled. Bald eagles are now classified in Pennsylvania as a threatened species instead of an endangered one, and our state’s current count stands at 252 known nests.
Birders’ “beloved Wissahickon”
This year, one of these nests was right in the Wissahickon Valley, though Pfeffer wouldn’t divulge its exact location.
“It’s not general knowledge where the nest is for good reason,” she said, noting that the eagles are still federally protected, and that human visitors can easily frighten the nesting birds and their young.
Pfeffer, a Willow Grove resident, has been birding throughout the region for decades, and offers birding tours through her own company, Birding With Ruth. She has led walks for the Friends of the Wissahickon, and is currently the birding instructor at Morris Arboretum.
“There’s a lot of interest in birding, and of course it’s a wonderful place to go birding,” she said of the Philadelphia area. “In the birding world, we call the Wissahickon ‘our beloved Wissahickon,'” she added. “I’ve birded there since I was 8 years old.”
The Philadelphia eaglets
According to Pfeffer, the Wissahickon nest had two eaglets that fledged less than a month ago, taking flying lessons from their parents. In a nest with multiple eaglets, Pfeffer explained, it’s especially important to protect the adults, because without two adult eagles to fill the hungry beaks, the nestlings are unlikely to survive.
Bald eagle nests are marvels of nature, weighing up to 2,000 pounds. Birders can observe the eagles’ high-flying courtship in December, with breathtaking dives that can exceed 100 miles per hour. Their eggs must incubate for 35 days in some of the coldest weather of the year, with the male and female taking turns warming the eggs.
An adult bald eagle, with its startlingly large brown body and distinctive white head and tail, can have a wingspan of up to eight feet. Pfeffer noted that the Wissahickon juveniles are likely to stay in the area for awhile, but birders shouldn’t look for a white head yet: the young birds don’t get their trademark snowy plumage until they’re about five years old.
Sharp-eyed locals might catch a glimpse of the eaglets if they look carefully at passing turkey vultures—the young bald eagles, which are larger than the vultures, sometimes share the same thermals as they soar.
Bald eagles eat mainly fish, but they’ll also scavenge meat where they can find it: Pfeffer said one park visitor sighted one of the adults with a cottontail rabbit in its talons.
The eagles’ tendency to return to their own birthplace to breed means there’s a good chance that Philadelphia’s bald eagle population will grow in the coming years, so Pfeffer touts the importance of “bald eagle etiquette.”
If you spot a bald eagle, whether it’s nesting, roosting or hunting, keep your voice down and stay a good distance away. The Game Commission says using binoculars is always best: eagles startled away from their nests by human activity (sometimes by irresponsible viewers who want to take pictures of eagles in flight) can hurt themselves when they take off too quickly, and the eggs or eaglets left behind can suffer or die if the parents don’t return quickly.
Pfeffer said there are many people in the Philadelphia region who have never seen a wild bald eagle, but as the species returns to the area, “that’s something that’s going to change.”
“They’re very impressive, they’re the symbol of our country, and I find them to be majestic,” Pfeffer added. “No matter how many eagles I see, I still marvel at it, and always will.”