Ospreys on the Rise: Group for the East End Documents Dramatic Increase in Osprey Populations

Osprey photo c/o The Group for the East End

August 26, 2018
By Beth Young, East End Beacon 

If you think you’ve been seeing more ospreys on the East End in recent years, the data bears this out — over the past four years, the Group for the East End has recorded a 50 percent increase in the number of ospreys nesting here.

Ospreys, known also as ‘fish hawks,’ were dramatically influenced by the use of the pesticide DDT, in use throughout the mid-20th Century, which caused the thinning of eggshells of birds throughout the country.

The dramatic decline in osprey populations due to DDT in the 1950s and 1960s lead to the pesticide being banned in 1972. Ospreys were listed as endangered in New York State in 1976, and, by 1995, due to successful conservation efforts, their status was downgraded to ‘species of special concern.’

“When I began at The Group in 2010, a reporter called to inquire about the status and size of Long Island’s osprey population, specifically on the East End,” said Group for the East End Vice President Aaron Virgin. “Unsure of the approximate size, I checked with the NYS Department of Environmental Conservation’s Division of Wildlife to see if they had an answer. I was told flyover censuses had stopped in the mid-90s after it was clear the population has stabilized.”

Since 2014, staff and volunteers from Group for the East End, The Nature Conservancy, Eastern Long Island Audubon, North Fork Audubon, and staff from town agencies have gathered osprey breeding data on eastern Long Island.

From July 1 through early August, the Group studies the five towns of East Hampton, Riverhead, Shelter Island, Southampton and Southold, visiting and revisiting known sites while searching for new ones. Of the 519 known sites in the Group’s database, 420 were active or of in potential use in 2018.

Five-year averages for the total number of nesting sites include 28 in East Hampton, 12 in Riverhead, 64 on Shelter Island, 106 in Southampton, and 196 in Southold.

The densest population of breeding ospreys is in Southold Town, which includes Fishers Island, Plum Island and Robins Island, where 60 known nest sites are found on the three islands alone. Southold Township is the birthplace of roughly 48 percent of all young born on the East End, due to the large number of creeks, coves and small bays within its boundaries. 

Shelter Island boasts the highest nest occupancy rate across the East End, with 80 percent of its nests full this year. According to The Group, nearly every site had a pair of birds and the ones that are unoccupied were likely put in place with this last two years.

Riverhead had the fewest nests, with 19 in 2018. Slightly more than half were occupied this year. This is due to the town’s large shoreline frontage on the Long Island Sound, where there are only roughly one dozen osprey sites, due to strong winds and surf during storm events, and minimal habitat along the Peconic Bay.

The largest East End town, Southampton, has had a very steady population during the past 20 years, a testament to The Group’s earlier days in osprey conservation, where Southampton was one of The Group’s prime spots for installing osprey nesting poles.

Perennial areas along Dune Road, Shinnecock Bay, Mecox Bay, along with newer sites on Scallop Pond, Long Beach and North Haven have kept the osprey population not only stable, but modestly increasing, particularly in the backcountry areas of Water Mill and Bridgehampton.   

But the ospreys in East Hampton seem to have the most productive lovemaking. Productivity is rated on the basis of the number of offspring produced each breeding season — if the ospreys produce one offspring in a season, they’re given a rating of “1” for the year, an indication that the breeding rate is stable.

But East Hampton leads the East End with a five-year average of 1.58, and a spike to 2.04 in productivity in 2017.

“Without question East Hampton appears to be showing the fastest growth, particularly in the Accabonac Harbor area where more than a dozen nests could be observed from a single spot this past summer,” said Mr. Virgin.     

In general, primarily in Southold, there has been an uptick in birds nesting in trees and on utility poles over the past five years, a situation that often leads to much public controversy if nests are disturbed by utility workers.

“Nesting in trees we want, which is what some osprey once did, but nesting along electrical lines not so much,” said Mr. Virgin, who noted that nesting osprey are not the cleanest birds and repeat visits to the nests with wet fish can lead to electrical shortages, sparking fires and resulting in death of young who are unable to fly.

“I learn about a few instances each year, but PSEG has become a good partner by working with the local community to safely remove a nest and replace with a nesting platform disc,” said Mr. Virgin. Earlier this year, the removal of a nest on a utility pole on Route 24 in Flanders sparked public outcry, but after the installation of a new pole and platform, by late July a lone chick was ready to fledge. 

Group for the East End attributes the robust increase in osprey populations to changes in fishing regulations for menhaden, known locally as bunker, a small fish that is often predated by bluefish and striped bass, and by ospreys, whose diet is comprised of 99 percent fish.

The Group is now looking to see if the birds will transition from the nesting platforms back to their original nesting places.

“On average, I receive an inquiry a week seeking information about how to place an osprey pole on private property or to see if someone has the right habitat,” said Mr. Virgin. “The Group is very particular on where to place a new pole, as our goal over the past five-year study has been to see if pairs will return to nesting in trees, old boat docks, and on other natural areas or places in disrepair. At some point it would be nice if osprey could make it on their own and with the current robust population we may be near that time.”

This year, volunteers and staff conducting osprey surveys have also seen an uptick in bald eagles throughout the East End.

“This was the first monitoring season where we encountered adult bald eagles at multiple sites, including Scallop Pond in Noyac, Hubbard Creek in Flanders, and Kellis Pond in Bridgehampton,” said Mr. Virgin. “I have heard of other adult bald eagle sightings on the North Fork, Plum Island and points further west.” 

Bald eagles not only compete with osprey for food, but they are well-known thieves that attack other birds shortly after they catch fish and are carrying it back to their nest. Eagles have been well-documented attacking and killing young osprey in their nest, both out of dominance and for food.

“It’s going to get very interesting very quickly once a critical mass of bald eagles are breeding on the East End. It may not happen next year or within the next five years, but it’s coming,” said Mr. Virgin.

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