Ospreys struggling from Long Island to Chesapeake as menhaden, a vital food source, become scarce

Late one afternoon toward the end of August, Don Riepe maneuvered his 22-foot skiff around the marshy islands of the Jamaica Bay Wildlife Refuge in Queens, where he had been the manager for 25 years.

He slowed as he passed an osprey platform built on a tiny islet of spartina grass and sea lavender. The osprey pair that nested there had not produced any chicks this summer. At the next nest on another patch of marsh, another osprey couple had raised no chicks.

Farther on, Riepe cut the motor near a platform he had set up six years ago. That first year, the osprey parents, who mate for life, had reared four chicks. Every year since then, they had produced at least two. "This year, nothing," he said.

Riepe regularly monitors 25 osprey breeding pairs during his patrols through the refuge. Twenty of those pairs produced no surviving chicks this season. And in each of the remaining five, only one hatchling survived to fledge.

"Last year wasn't good, but this year was a real population crash," he said. "There’s not enough food for them."

Riepe and other conservationists, as well as some fishermen, believe the osprey chicks' poor survival rates this breeding season is directly related to the sudden and dramatic decline in Atlantic menhaden, also known as bunker. The fish form the bulk of a coastal osprey’s diet, and are an important food source for whales, dolphins, striped bass and other marine species.

Ospreys chicks not surviving

Populations of ospreys and other birds of prey across the globe were plummeting 60 years ago because of the widespread use of the pesticide DDT. The chemical was banned in the U.S. in 1972, thanks to the ecologist Rachel Carson’s book "Silent Spring," and ospreys, eagles, falcons and hawks slowly began to recover.

Long Island and the East End in particular, "with its protected shallow bays, was just ideal habitat for ospreys to forage and to breed," according to John Turner, senior conservation policy advocate at the Seatuck Environmental Association. Decades after the DDT ban, ospreys have once again become a common sight on the Island, becoming one of the most visible achievements of the environmental movement.

But today these birds of prey are once again at risk. 

All through the mid-Atlantic, from the Chesapeake Bay to New Jersey to Long Island, ecologists, birders and boaters have reported significant declines in the number of osprey nestlings during the summer breeding season. They also say the loss of menhaden is a significant cause: osprey pairs are not finding enough of these calorie-dense and nutrient-rich fish for their young, and the young have been starving.

Last year the 385 osprey nests monitored by the environment organization Group for the East End averaged one chick each. That was down from 1.3 chicks per nest in 2022 and 1.7 in 2020. 

Some observers have reported worse outcomes. Joanna Steidle, a photographer and videographer from Southampton who films Long Island coastal wildlife, said in the past three years she hasn’t seen surviving chicks in the four or five nests she regularly watches on the East End.

Chris Paparo, who manages the seawater lab at Stony Brook University, regularly monitors and photographs a breeding pair he calls Ral and Mary, who nest near Old Fort Pond off Shinnecock Bay. Three chicks hatched in May, but later that month Paparo reported to the ospreys' followers on his Facebook page that Ral was bringing freshwater fish to the nestlings. "Considering this nest is surrounded by saltwater, the fact that he’s turning to freshwater prey is a sign that bunker aren’t around in large numbers," he wrote.

None of the chicks survived. After the last one died in June, he spotted Mary perched on a wood piling, holding the dead chick in her talons. 

"She sat there staring at it and calling loudly," he wrote. Then she flew around the pond, still holding the chick, returned to the nest, then flew to the piling again, "continuing to look at the lifeless chick while calling out repeatedly. It was a difficult thing to witness." 

Menhaden schools have diminished

In flush years, menhaden swim close to the surface in large schools, tens of thousands of silvery bodies darkening the water. An oily fish that can grow up to 15 inches long, they are not palatable to humans but are essential to the marine food web.

They are a favorite of ospreys and are also eaten by eagles, cormorants, terns and gulls. Larger fish like striped bass and tuna prey on them, as well as whales, dolphins and sharks.

In 2012, in response to concerns about overfishing, the Atlantic States Marine Fisheries Commission, which manages ocean species, for the first time capped the total weight of menhaden that could be taken.

The menhaden recovered quickly, and in the following years, Long Islanders witnessed a remarkable resurgence in the number of whales and dolphins swimming offshore — chasing the plentiful schools of menhaden. But the limit was increased in 2023, and soon after, conservationists and sport fishermen noticed smaller menhaden schools and smaller fish.

Fishermen and advocates point to one industrial fishing operation, Virginia-based Ocean Harvesters, for depleting the menhaden schools, effectively getting a bulk of the allotted harvest on the East Coast. The company's processing partner, Omega Protein, grinds them up for fish oil supplements, fertilizer and animal feed.

"These huge ships are taking millions of fish," Paul Eidman, a charterboat captain who frequently traverses the New York Bight, said.

Eidman, the founder of the conservation group Menhaden Defenders, is advocating for a halt on industrial menhaden fishing within 12 miles of the shoreline until populations recover. "If we had a healthy, robust bunker fishery," he said, "we certainly wouldn’t be witnessing the starving ospreys, that's for sure."

Monty Deihl, the company’s CEO, wrote in a recent op-ed that "the coastwide stock is not overfished," and that "many other factors could contribute to failed osprey nests, including pollution, disease, and nest competition."

The New York State Department of Environmental Conservation told Newsday that distributions of menhaden along the East Coast can change as environmental conditions change, and that while bunker sightings locally have decreased, landings in northern states such as Maine have increased.

Preparing for perilous migration

In November the Atlantic States Marine Fisheries Commission will meet to decide if the coastwide cap on menhaden should be reduced, and if the cap on industrial operations in the Chesapeake Bay should be cut as well.

Local conservationists like Turner, of the Seatuck Environmental Association, and Carl LoBue, ocean and fisheries director at The Nature Conservancy, are hoping for steeper cuts. Ospreys and other birds are under stress from global warming, habitat loss, collisions with cars and windows, and pesticides and herbicides. The food stress they’re experiencing, however, is one hazard that has a relatively simple solution, experts point out. "We can’t just snap our fingers and change the climate," LoBue said. "The only tool managers have is to cut back on the number of fish we kill."

By now, the ospreys that have spent their summers along New York’s coasts have begun to migrate to warmer climates — first the females leave, then the males, and finally, by October, the months-old juveniles. Most will head to Central and South America — Riepe has tagged and tracked one Jamaica Bay osprey to Colombia and another to Venezuela. The long journey requires substantial stores of fat, and some of the undernourished adults, and perhaps more of the underfed young, will not make it.

In March, the surviving birds will fly north again, meeting up with their same mates and returning to the same nests they left the previous fall. They will be hunting for nice-sized menhaden to rebuild their energy and, in time, to feed their hatchlings.