Talk about populations on the rebound.
Down to only 50 nests in 1974, the state’s ospreys have recovered so much that a new report shows a total of 515 active nests in New Jersey — about equal to the historic population of the birds.
Decimated by pollution, including DDT, the osprey population has been growing since the banning of the pesticide and the steady, if slow, cleanup of the state’s and nation’s coastal waters since the passage of the Clean Water Act.
The report by the New Jersey Division of Fish and Wildlife’s Endangered and Nongame Species program and the Conserve Wildlife Foundation found 376 nests where volunteers and biologists counted 670 young produced by the pairs of nesting birds.
“At the beginning of nesting surveys each year, I attempt to speculate on how well ospreys are doing,’’ said Ben Wurst, CWF’s habitat program manager. “Well, ospreys made my speculation seem quite dismal. I’m astonished by their continued growth while living in very close proximity to humans.’’
The majority of the nests are, while the most productive are located along the Delaware Bayshore, where 116 young were counted. Forty-two new nests were found this year.
Unlike more secretive bald eagles, ospreys seem to thrive in densely populated New Jersey where people tend to crowd the coast.
“They nest very close to people,’’ Wurst said. “A lot of people have them almost in their backyards next to the marshes.
Ospreys also end up nesting in more urban areas, with nests in the Hackensack Meadowlands and many tributaries of the Delaware River, according to David Wheeler, executive director of the CWF. “What’s great is they are able to adapt to urban waterfronts,’’ he said, noting one nest is near a power plant owned by PSEG Power in Jersey City.
“Only decades ago, ospreys had drastically declined across New Jersey, and the nation, which makes their continuing recovery all the more remarkable,’’ he said. “The ospreys’ expansion speaks both to the improving water quality of our estuaries and rivers, and the dedication and leadership of our state and CWF biologists and volunteers.’’
The significance of the recovery of the bird, listed as endangered by New Jersey in 1973, is that ospreys are the quintessential indicator of the health of an ecosystem. “They’re sort of the new age canary in the coal mine,’’ Wurst said.
What also has helped the restoration is the building of manmade platforms, where the birds like to nest. More than 150 have been put up in New Jersey. “As a result, we have seen the range of the osprey strengthen,’’ Wheeler said.
At this point, at least 75 percent of the nesting osprey, and maybe as high as 80 percent, nest on the manmade structures, Wurst said. They also choose to nest on utility poles and communication towers, he said.
Based on the survey, the foundation projected population growth around 10 percent, which is about equal to the rate since around 2009.