New Jersey Ospreys Bounce Back from Near Extinction

New Jersey ospreys, a population that suffered from widespread use of DDT-based insecticides and lack of sufficient prey, have bounced back from near extinction, according to a recently released report.

The 2014 Osprey Project Report estimates that New Jersey's osprey now number at about 567 pairs, up from just 53 pairs in 1973. That means these birds, also known as fish eagles, are recovering, with about two birds being born per nest - that's twice the required number for the species to maintain a stable population.

"The comeback of these magnificent birds continues to inspire us, especially in combination with the parallel recoveries of bald eagles and peregrine falcons," Conserve Wildlife Foundation (CWF) executive director David Wheeler, said in the organization's blog.

CWF of New Jersey and the New Jersey Division of Fish and Wildlife conducted ground surveys in June and July of this year to determine the population size of these raptors.

A total of 686 chicks were born this year, and of the 420 active nests recorded, 339 produced an average of 2.02 fledglings per active nest. That's up from 1.92 last year and well above the minimum productivity rate of 0.80 young/active nest needed for a stable population.

In 1974, the osprey was added to the New Jersey Endangered Species List when use of DDT-based pesticides affected the productivity of the birds. According to a release by the state of New Jersey, DDT (dichlorodiphenyltrichloroethane) inhibits calcium metabolism in birds, thinning the eggshells and causing them to break easily under the weight of the baby bird, resulting in failed reproduction.

Reduced fish populations - especially of Menhaden or "bunker" - also contributed to the decline of New Jersey ospreys, with the bird's productivity known to rely on the health of coastal fisheries. According to the report, the osprey's comeback is an indicator that species in New Jersey's coastal an inland waters are recovering.

Conservation efforts as well as the ban on DDT use were also attributed to the boom in the birds' numbers.

"The results from this year were really positive for ospreys," biologist Kathleen Clark, from the Division of Fish and Wildlife, told The Inquirer. "You can never complain when you're about twice the minimum productivity needed, so we can expect the population to keep growing."

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