Fish and Chicks
The Story of the Maurice River Osprey
In the 1940-60's the organochlorine pesticide DDT was sprayed on coastal marshes in an effort to kill mosquitoes. The DDT had an adverse effect on the reproductive system of female osprey, causing their populations to plummet. By 1974 the population was about 65 pairs in NJ (from Paul Spitzer) of a historic population about 400-500 nests (NJ only). Rachel Carson’s 1962 best seller Silent Spring alerted people to the impending devastation of synthetic chemical compounds.
Species: Osprey (often called Fish Hawk)
Latin Name: Pandion haliaetus
Habitat: wetland – open water
In 1973 the EPA finally banned DDT. This ban and the implementation of osprey recovery programs like that of Citizens United to Protect the Maurice River and Its Tributaries, Inc. have led to major strides in recovering osprey populations to former numbers.
Field Markings: Head white with dark brown mask over yellow eye, back and wings dark brown, underside mostly white with dark brown patches at wrist and on wing tips. Juveniles have orange eyes, speckled feather on back, and tawny vs. white feathers on cap and breast.
To reintroduce osprey to an area of former abundance, first wildlife biologists removed eggs of healthy adult birds from regions that had been spared the toxic spraying. Then they placed them in nests of birds who had for a long duration been unsuccessful in incubating their eggs. These adults raised these adoptees as their own. The juveniles imprinted to the region in which they were raised and thus established new colonies of healthy birds.
Hatchlings: immobile, downy, eyes open
Today, a key factor in maintaining and increasing osprey numbers is the construction of osprey platforms. Our organization has been making nesting platforms since 1986. Originally we had just a handful of volunteers. Over the years we estimate that more than 100 different volunteers have helped with the project.
Mating: primarily monogamous
]Nest Style: trees and an infinite variety of man-made structures near water including nesting platforms designed for their use.
We erected and maintain over 30 nests, and we share our design with countless other organizations. This photo was taken when we taught PSE&G and The Nature Conservancy how to erect platforms. We have built at least 35 nests for other groups and agencies.
Incubation: About 35 days (5 weeks), by both parents, primarily female
Fledging: 7-8 weeks of age
Number of Broods: 1
In February and March we inspect nesting structures for predator guards. We remove nesting materials from nests that are too large and heavy, and we erect nests adjacent to locations where young pairs have selected poor structures to nest upon.
NJ Species Status: upgraded from endangered to threatened in 1985
In April, we count eggs.
Clutch: usually 3 sometimes 4
Survival: 1.3 average
Maurice River Survival: over 2
And in June we band osprey chicks. In 1986 when we started the project, about 3-6 chicks were fledged on the Maurice River; in 2002 we banded a record 60 chicks (2003's cold and rainy spring caused severe nesting failures only 33 were banded).
Life Span: as long as 20 years
Migration: South America
Range: found on every continent with the exception of Antarctica
Today scientists have more sophisticated means of tracking osprey than solely by the method of banding. Citizens United volunteers helped capture this Maurice River osprey, enabling the University of Minnesota and the NJ Endangered and Non-game Species Program to equip it with a solar-powered satellite transmitter.
Weight: 3.5 - 4 lbs.
Length: 22 inches
Wing Span: 54 inches
In the middle of August, birds begin to migrate, and by the middle of September most osprey are well on their way to their wintering grounds in South America.