Eagles (the flying kind) are making huge gains in Pennsylvania, a major bird census shows

With a head whiter than the clouds veiling the faint blue sky, a bald eagle pursued an egret in an aerial-ballet chase. Opting for prudence over valor, the white-winged heron decided to exit the stage for safer territory.

It was a drama worthy of a Nature episode — save for the fact that the eagle appeared to be flying faster and higher than a jet whose belly looked like it was about to scrape the cantilevers of the Girard Point Bridge.

The venue was FDR Park in deep South Philly, near where those other Eagles practice and play.

Local bird experts say that eagles appear to have built a nest in an undeveloped area of the park — which is undergoing a contentious $250 million makeover, a joint project of the Fairmount Park Conservancy and the city’s parks and recreation department. However, project officials question whether eagles were involved in the construction.

What is clear is that eagles have made an astonishing comeback in Pennsylvania and the Philadelphia region.

In the early 1980s, at most two nesting pairs were identified in the entire Keystone State, both in sparsely populated Crawford County, on the Ohio border.

In a statewide survey that began last year, 40 nests have been verified in just Philadelphia and its four neighboring Pennsylvania counties — four of those in the city itself — Manny Dominguez Jr., a Philadelphia coordinator of the third iteration of the Pennsylvania Bird Atlas, said last week.

The results are preliminary: The atlas, a massive census that attempts to identify all species that nest and breed in Pennsylvania, is a five-year project, and this is only year two. The results won’t be published until 2031.

Those eagle nesting numbers almost certainly will grow, and the atlas surveys may have a whole lot to do with the resurgence of the once-endangered eagles and their archenemy ospreys.

Some birds migrate thousands of miles, mostly in the dead of night. Some can talk. Others can fly at turnpike speeds. But no known species has been able to fill out a census form.

Thus, the Pennsylvania Game Commission, the Hawk Mountain Sanctuary, and the Pennsylvania Society for Ornithology have enlisted 2,400 census-takers (so far) to do the canvassing, according to Amber Wiewel, the statewide coordinator.

Pennsylvania is one of several states, including Maryland and New York, that undertake five-year-long surveys every 20 years to identify which birds are living where. Hundreds of species pass through Pennsylvania annually, but the so-called breeding bird atlas is confined to nesting tenants committed to building nurseries, not the day-trippers. For census purposes, the state is divided into about 5,000 three-square-mile blocks.

Wiewel estimated that about 180 nesting species will have been identified by the time the survey is complete. That would be similar to the current number, but she suspects that the state will lose and gain a few as a result of development patterns, food availability, reforestation, and climate change.

This is the third Pennsylvania atlas, the first one commencing in 1984, and the sequel in 2004. The five-year study period is meant to allow adequate time without continuing “in perpetuity,” Wiewel said.

Confirming that a species has taken up residence requires “direct observation of breeding behavior or activities like nesting, incubation, or feeding young,” Dominguez said.

Volunteers can join the project at any time, and participation is open to all, providing they follow the protocols to verify actual nesting. And while it may have recreational and educational values for bird enthusiasts, it has overarching purposes, its organizers say.

“One of the main goals of the atlas is to provide data to the state for conservation priorities,” Dominguez said. “They certainly have informed policy … not just for eagles and osprey, but all the species that breed here.”

After the passage of the Endangered Species Act in 1973, the eagle population began a slow recovery across the country, following decades of decimation due to development, hunting, and DDT contamination.

In Pennsylvania‘s first atlas, a modest comeback was evident. By 1989, 11 nesting pairs had been identified, most of them in the northwestern part of the state, but one pair in Lancaster County.

In the 2004-09 census, the numbers jumped to 275 nesting pairs, three of those in Philadelphia.

The eagles hopped off the Pennsylvania endangered list in 2014, but they remained on the Garden State list until four months ago. (That decision was opposed by the New Jersey Conservation Foundation, which warned that avian flu was a threat to eagles.)

And the population appears to be booming in Pennsylvania. In just the first year of this atlas, over 400 nests have been identified in the state.

Locally, in the second atlas, only nine nests were confirmed in Philadelphia, Bucks, Chester, Delaware, and Montgomery Counties. So far, that number already has increased to 40 — and climbing.

Dominguez said there were “numerous observations of bald eagles” building a nest in FDR Park.

A large nest is evident in a pine tree on the western side of the park, in the area of the former golf course. In an emailed statement, however, Fairmount Park Conservancy spokesperson Cari Feiler Bender said, “The project’s senior ecologist carefully observed the nest over the last few days and has determined that the nest is unoccupied and is not deep or wide enough to be an eagle’s nest.” The statement added that project officials would continue monitoring the site.

Ornithologist Keith Russell, Audubon Pennsylvania‘s program manager for urban conservation, said that “based on observations made over several months … eagles are the birds currently using the nest.” It is possible, he added, that they may not lay eggs until next year.

Avigail Milder with the Save the Meadows organization, which opposes the park plan, said even if the pine tree is spared, “the whole area is going to be a construction site” that would disrupt the eagles.

The city may get a fifth confirmed nest in any event, said Lamar Gore, park superintendent at the John Heinz National Wildlife Refuge. Gore says he suspects that the eagles have built another one in the refuge.

Regardless, he says, he is thrilled by what he is seeing at the Heinz center and elsewhere. Along with eagles, the once-endangered ospreys have been prospering in Pennsylvania. Their nesting numbers increased tenfold, to 148, in the second atlas compared with the first.

So far, at least 229 nests have been identified in the third atlas, Wiewel said, and that number in all likelihood will grow significantly.

Said Gore: “Both the ospreys and the eagles have made quite a comeback. I love it.”

Volunteers need not sign up to participate.

The Volunteer Handbook has complete instructions, including a “quick start guide” on how to use the eBird app.

For those who don’t have access to eBird, paper forms are available from local coordinators — [email protected], in Philadelphia.

Form PDFs are available on the PA Bird Atlas Discussion Group on Facebook under “files” or via sinomn.com/birdatlas.