How the bald eagle came back
Once reduced in New Jersey to a single breeding pair, the raptor returns from the brink
With its distinctive white head and tail and chocolate-brown back, the bald eagle is an increasingly familiar sight to anglers, kayakers and other recreational users throughout the Delaware River Watershed, including New Jersey.
Statewide, the bird has bounced back from a single breeding pair in Cumberland County in 1970 to 267 pairs in 2022, 20 more than in 2021, thanks in part to a national ban on the pesticide DDT in 1972. DDT and other pesticides, whose use became widespread in the 1940s, prevented most breeding by making eggshells too thin to be sat on by incubating parents, and decimating the population.
≋ Play to hear the eagle’s call. Credit: Ted Keyel for the Macaulay Library at the Cornell Lab of Ornithology.
In the last 50 years, the bird has also benefited from cleaner water in the Delaware River and its tributaries, thanks to the federal Clean Water Act of 1972, fostering the recovery of the fish and waterfowl that the eagle feeds on.
The bird’s recovery has been a conservation success story, and while it is no longer listed as endangered or threatened by the federal government, the national emblem still generates excitement when it’s seen perching on a riverbank tree or hunting over water.
That popularity helps to protect it, said Kathy Clark, supervising biologist at the Division of Fish and Wildlife in the New Jersey Department of Environmental Protection.
It’s got charisma
“It’s one of the charismatic macroinvertebrates,” she said. “If only all endangered species got that kind of respect, things would be very different. People love eagles, they care about them, and you really need to have that to have a successful population rebound.”
Clark said public admiration for eagles makes it more likely that people will report any injured birds or attempted egg stealing to wildlife officials. And she said developers are more likely to meet public resistance if they plan to build on land where an eagle is known to nest. That pressure is particularly important since about three-quarters of New Jersey’s bald eagle pairs nest on private land, she said.
By contrast, the public doesn’t much care about other endangered species such as freshwater mussels or timber rattlesnakes, and that’s one of the reasons that their populations are harder to sustain, Clark said.
In recent years, New Jersey has seen 10 to 20 new nesting pairs of eagles per year, a fact that Clark called “pretty amazing for a state like New Jersey.”
Caution in New Jersey
According to the 2022 report from the fish and wildlife division of the DEP, 250 pairs of eagles laid eggs during the year, an increase of 28 from 2021. Eighty-three percent of the nests produced a total of 335 young, resulting in a productivity rate of 1.42 per nest, above the rate needed for the population to remain stable.
The 250 active nests confirmed in 2022 were more than double the number 10 years earlier, when 119 active nests were counted.
As in recent years, most nests were in South Jersey, particularly within the Delaware River and Bay region, and the majority of the nest sites were on private land.
The 250 active nests confirmed in 2022 were more than double the number 10 years earlier, when 119 active nests were counted.
The 267 pairs that were monitored in 2022 included pairs that had active nests as well as those that maintained nest territories but did not lay eggs. Fourteen new territorial nesting sites were confirmed in the southern region, 10 in central New Jersey, and five in the north.
The federal government removed the bald eagle from its list of endangered species in 2007, reflecting a strong gain in the population throughout the United States. But in New Jersey, the bird remains state-endangered during the breeding season and state-threatened for the non-breeding season. The greatest threats to bald eagles in New Jersey are disruptive human activity in nesting and foraging areas and habitat loss, according to the DEP.
Recovery strategies
Still, its recovery is an encouraging environmental story, said DEP Commissioner Shawn LaTourette.
“The continued growth of New Jersey’s bald eagle population is an inspiration to all of us and is a direct result of strong environmental protection laws, firm partnerships, innovative scientific techniques — and the dedication of many volunteers who devote much of their time to monitoring and protecting eagles,” LaTourette said in a statement.
Eagles may yet have to adapt by getting used to being closer to other birds or humans.
Larry Niles, an independent wildlife biologist who headed the bald eagle program at the DEP in the 1980s, said his team helped the recovery by introducing young eagles from Canada into the New Jersey population.
Niles also removed eggs from eagle nests to prevent their thin shells being crushed by incubating parents. The eggs would be artificially hatched in a lab, and the young birds would then be installed in the nests two weeks later, he said.
“To stop the egg being crushed, I would climb the tree, take the egg out, put in a fake egg, and then come back two weeks later and put in chicks, and the eagle would just think that the egg hatched,” he said.
Niles said a second nest appeared in about 1990, and the population quickly increased after that.
Plenty of suitable habitat
The state has a lot of good habitat, Clark said, especially along its Delaware Bayshore, where tidal rivers bring in good numbers of fish and wildfowl for the eagles to feed on, and which is interspersed with farms and woods that attract and shelter the birds. With eagle numbers continuing to increase, naturalists are watching for signs that its population is reaching the state’s capacity. If so, the birds may compete for nest space or food with other successful species such as ospreys, as they have in the Chesapeake Bay region of Maryland and Virginia.
With eagle numbers continuing to increase, naturalists are watching for signs that the population is reaching the state’s capacity.
That hasn’t happened in New Jersey yet, Clark said, but the population may get to the point where eagles have to adapt by getting used to being closer to other birds or humans than they were when numbers were lower.
“Eagles are going to have to adapt, maybe tolerating other birds and people closer than they really want because that’s where the nest site is and the food is there,” she said.
This article is part of a special series by NJ Spotlight News and funded by the William Penn Foundation. Go to njspotlightnews.org/Delaware-Watershed to visit the project homepage. Send us your stories and photos about the Delaware River region.
