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Jul 21, 2015 3:21 PMPublication: The Southampton Press

Osprey Nesting Has A Banner Year

Aaron Virgin from Group For the East End is surveying osprey nesting success on the East End. M. Wright
Jul 21, 2015 4:12 PM

Ospreys are having a good year.

Throughout the South Fork and East End, nesting pairs of the fish-eating hawk are seeing very high success rates, in terms of the number of young-of-the-year chicks that are surviving to fledging size.

Dozens of pairs of the once endangered hawks are nesting on the East End and, thanks to the high levels of survival of this year’s brood, as many as 150 or more new young ospreys are expected to join the southward migration from the region this fall.

“It’s off the charts,” said Aaron Virgin, vice president of the Group for the East End, who conducts annual surveys of osprey nesting success and locations. “It seems like there’s two [chicks] in every nest. Some have three—which is usually very rare, for three to survive.”

Like many other migratory species, the ospreys arrived back on the East End later than normal this year—though the birds were not slowed in their return by winter cold that persisted into April, but by a lack of early spring pressure fronts and the southerly winds they bring, which help carry the birds northward.

“I was getting a little depressed—we thought this year might be not so great,” Paul D’Andrea, a naturalist and land steward for The Nature Conservancy who also tracks osprey breeding, said recently. “But then they came back and … things look good. A lot of nests that had been empty for a couple of years have occupants this year.”

Surveyors reported that as many as 30 nests that had long been abandoned are again hosting an osprey family this year.

Osprey watchers say that the success of the birds’ breeding efforts this year can likely be chalked up to a number of helpful factors combining to make raising young ospreys a little bit easier.

An outsized abundance of one of the osprey’s favorite meals—a fish called menhaden, or bunker—has made finding food for their young an easy task for the adult ospreys. The late spring and early summer temperatures have also been relatively mild, not too hot, which can stress young birds still unable to fly. And there have not been any strong storms, which can batter exposed nests.

Most ospreys nest on tall poles specifically built to help the birds nest on stable platforms. The poles, thousands of them across the Northeast, have been erected by a variety of environmental and wildlife groups and have played a key role in the osprey’s population rebound.

Before poles, ospreys mostly nested on the thinning branches of dead or dying trees with few leaves, though they occasionally would nest on the ground in places where predators like raccoons and foxes are scarce, like Gardiners Island. At least one osprey family nested on the ground on the island this year as well, Mr. Virgin said.

Mr. Virgin, who previously worked for the Audubon Society, said that scientists have asked that more nesting poles not be put up, to help them gain a baseline control of nesting rates across the region.

About 40 pairs of osprey nested in trees last year. Tree nests can be tricky to spot, and since they do not typically survive their winter vacancy—unlike nests on poles—they have to be discovered anew each year.

The birds have also nested on a variety of other improvised spots, for instance atop duck blinds, telephone poles, chimneys and marinas’ Travel-Lift boat haulers. Such improvised housing can be a problem for nesting success—unwelcoming hosts or mechanical devices that may be suddenly needed for their intended use can prematurely doom a nest—so Mr. Virgin says there is a debate about whether a long-term goal should be to get the birds back into the tree-nesting frame of mind.

Tree nests can be unstable, particularly since ospreys tend to choose decaying trees that are prone to losing limbs, and nests, in storms.

The banner year of reproduction does not mean that there will be an osprey real estate bubble next year as young line up for space on open nesting poles and treetops.

Typically, just one in four young ospreys will survive the bird’s nearly 10,000-mile round-trip winter migration to South America and back. If the bird does survive that first year, the expected lifespan of an adult osprey is 13 to 16 years.

A Hamptons resident may spy an osprey or two, sometimes three, gliding over the same pond or embayment as the birds search for fish or stretch their wings, but during the summer months they remain largely isolated to their family groups. But each winter ospreys gather in Cuba and Haiti by the thousands and migrate southward from there in large flocks.

Ospreys are the only raptor that travels long distances—up to 1,500 miles—over water. A male osprey tagged by researchers on the North Fork in 2010 has been tracked on his annual round trip between Long Island and Venezuela for five winters now.

Even before this year’s soaring success, ospreys have been counted as one of the great success stories of environmental advocacy bringing a species back from the brink.

Osprey populations, much like bald eagles’, had plummeted to endangered species levels in the 1970s because of the ill effects of the chemical pesticide DDT building up in their bodies through the consumption of fish, causing steep declines in reproduction. Since the chemical was banned in the 1970s, ospreys have steadily rebounded and are now one of the most common birds of prey on Long Island, believed to already be back to nesting levels greater than in the years before the DDT collapse.

The East End, in particular, boasts a large and growing population of ospreys, and local scientists have shifted their tracking of ospreys from nervous observation for signs of trouble to trying to track the growth and other patterns of success.

“We’re trying to figure out how big the population can actually get,” Mr. Virgin said.

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Excellent news. I have seen a lot of them gliding overhead. They are handsome birds.
By Crabby (63), Southampton on Jul 23, 15 10:19 AM
pretty cool to be able to track the bird to venezuela and back

maybe we can strap on a go pro camera next time!
By llimretaw (118), watermill on Jul 23, 15 6:57 PM
We have a view of a nest near our house by Bull Head bay in Southampton that has 3 chicks in it. This is the first year since the pole was erected that the nest has been occupied.
By jojo12858 (1), Centerport on Jul 23, 15 10:04 PM