Conserve Wildlife Blog

Posts Tagged ‘DDT’

Early recovery efforts pay off

Thursday, February 16th, 2012
Program from 1970’s restores osprey population to historic numbers

by Ben Wurst, Habitat Program Manager

A helicopter hovers over an active osprey nest to count the number of eggs. Image courtesy NJFW.

The New Jersey Osprey Project began after the osprey was listed as an endangered species in 1973. In April 1974 an aerial survey was conducted to count the number of active osprey nests. The survey was conducted from Toms River to Atlantic City. The results were grim. Only five active nests were found. 10 years earlier there were over 50 in that same area. On all of Barnegat Bay in 1974 there was only one active osprey nest.

The heavy use of DDT in the 1950’s and 60’s was the main culprit in the decline of ospreys by affecting their ability to reproduce. When used in marine environments it was quickly absorbed by organisms and soils. It accumulated in the food web and because it was fat soluble it bioacummulated in predators, especially birds of prey. In short, it caused the thinning of eggshells which often broke under the weight of the incubating female. This threat, along with habitat loss and persecution caused the population to become almost extirpated from the state.