Historically New Jersey is thought to have had about 500 pair of nesting osprey, often referred to as fish hawks by the river folk. But by the early ’80s fewer than 50 pairs of osprey were left.

A chemical pesticide known as DDT, used to spray for mosquitoes, was absorbed by small organisms which were in turn eaten by fish. These poisons persisted in ever-greater concentrations as each animal up the food pyramid devoured its lower prey species. Finally, at the top of this hierarchy was the osprey

It stored the contaminant in its reproductive system with the end result that it laid eggs with very thin shells. The shells were so fragile that they could not support the weight of the bird, and therefore nests no longer produced young.

The same effect was seen in our local eagle populations.

In the late ’50s biologist and author Rachel Carson sounded the alarm about the use of synthetic chemicals and their ill effects on nature. In 1962. the book Silent Spring brought public awareness to the environmental problems caused by these substances. It wasn’t until 1972 that Congress finally banned DDT. To this day Car son’s writings are credited with igniting the environmental movement.

Carson essentially pointed to the fate of the osprey as being like a canary in a coal mine. In other words, the osprey was an environmental indicator of threats to human health. After all, like the osprey we, too, are at the top of the food chain. And we, too, rely on fish for a balanced diet.

Biologists began recovery programs to try and reestablish osprey to their former numbers. Several different techniques were used. Chicks were brought from healthy nesting populations to be raised by adults who survived but could not successfully reproduce. The birds imprinted (or formed a link with) their fledging areas and returned to raise young in an environment where DDT persisted but had been breaking down and had diminished in its toxicity.

Volunteers began to construct nesting platforms that were safe ha vens for raising young. The os prey’s nesting locations of choice are dead trees with clear views. For osprey, electrical poles seem to meet those criteria. Unfortunately, this often has tragic results. With a six-foot wing span, osprey can easily touch both wires and act as a conduit for the electrical current, and thus be killed.

Citizens United, un der the guidance of the N,J, Division of Fish & Wildlife’s Endangered & Nongame Species Program, has been a key player in the osprey’s recovery.

We began our osprey colony project in 1985. At that time, only about 3 chicks were fledging on the river each season. Today we band over 70 osprey chicks a year.

We have constructed nesting platforms that are used throughout New Jersey and our platforms have become the state’s official design. In fact, now the birds have imprinted to the design as well, so much so, in fact, that when we erect new nests in the spring, birds will often begin using them within an hour’s time.

We answer inquiries from all over the globe about assisting osprey; over 400 visitors a month go to our website for osprey advice. There we have made available engineered drawings of poles, predator guards, slide shows, and more.

Along Millville’s river-walk between Brandriff and Mulford Avenues, Citizens United volunteers put up an osprey nesting platform this past September. It is visible from the two foot-bridges along this stretch of the walk.

Ospreys are beginning to return from their wintering grounds in South America. Between now and the first week of April, we hope a pair of osprey will lay claim to this platform.

It is not until an osprey’s third year that it becomes sexually active. First year nesters often play house, building a nest but not raising young.

When the herring make their reproductive run on the river in the spring, osprey congregate between Brandriff Avenue and the Sharp Street dam at lower tides to capture fish for their meal.

So, if we don’t lure in a nesting pair this year they are almost certain to use the platform for feeding.If they do nest, river-walk hikers are in for a treat. So don’t forget your binoculars when you venture to the area.

And, remember to check out the three wood-duck boxes, too. We will be checking them soon for screech owls which, as cavity nesters, often use the same housing.

Our most recent addition to our website is a series of stories about each of the osprey nests on the river. It makes interesting reading; check it out here!

CU on the River!