By Lynda Hester-D'Orio
June 3, 1999

Wildlife managers in New Jersey have recently become aware of problems with the decline of the osprey population currently residing in the Garden State. Nests have been discovered with the skeletal remains of chicks suggesting a significant problem: some of them may be starving. Nature provides for many species to survive by having multiple offspring. It is not unusual that some will die due to natural causes, but this does not seem to be the case. Their numbers are declining. Birds are the indicators of the health of the planet, they are easy to study and provide a wealth of information on environmental health, so when a species like the osprey is at the top of the food chain, their population and health become an area of concern.

Volunteers and scientists are tracking the parents' behaviors to discover why the osprey, who normally produce a clutch of 3-4 eggs and may successfully raise 1-2 chicks, are now in the midst of a serious decline. The rate of chicks' survival is now estimated to be .88, down from 1.5 earlier in the 90's.

New Jersey now has about 250 nesting pairs of osprey in New Jersey and in order to grow the population, the success ratio of raising their young must go up over 1.0.

Although the osprey can eat reptiles, amphibians and even small mammals, these raptors have a very distinct food source they prefer. Ospreys live near rivers, lakes, streams and by the ocean. They are hunters, not scavengers, and prefer live fish as their main food. Their bodies have evolved into streamlined hunters, true birds of prey. They can have up to 6-foot wingspans to soar over the habitat looking for food. They will hover over their prey and then dive to catch it. They can't swim, but rather must judge the weight of their prize and use their strong talons to capture their slippery prey, lift it out of the water and fly to a safe roost to eat. One 10-oz. fish a day will keep them healthy.

Here in New Jersey, one of the fish osprey love to eat is the menhaden. This species is also the main source of food for striped bass. The menhaden swim close to the surface of the water, making them easy for the osprey to see from the sky and ideal in size and weight to pull out of the water. Wildlife officials are trying to evaluate whether there is a correlation to the management and protection of the striped bass and the depletion of the menhaden.

There is also a surge of the numbers of motor boating and pleasure crafts near the sensitive nesting areas of these birds, which may interfere with their behavior and affect the success of hatching the eggs. Female ospreys spend almost 90% of their time incubating the eggs while the male hunts for food. If noise is moving them off the nest, the eggs won't hatch. Pollution is a concern too; the quality of the water and the diversity of the fish population is critical to birds of prey.

Since the 1950's pioneers have fought to maintain the health of this species. It was determined that DDT in the eco-system affected ospreys as well as many other birds eggs. It was shown their shells became thin and the chicks would not hatch when the parents ingested DDT. Since the ban, many birds have experienced a comeback in their populations.

Corporations like PSE&G have, with the help of volunteers from their communities, erected nesting platforms to encourage breeding. These platforms discourage the birds from building nests on wires which, when soaked with wet nesting materials, become problematic and dangerous. Strong efforts are at work to save these birds.

The osprey population can be found on every continent except Antarctica. They can live as long as 25 years and usually mate for life. They will migrate thousands of miles to warmer climates in the winter. We speculate that the New Jersey ospreys travel down to Central and South America only to return to the North America to nest in the spring.

In the 1970's, ospreys were put on protected species lists. At one point a scientist had to bring in eggs from Maryland to supplement our own population which had dwindled at that time. It is clear that they are still in a fragile state of existence today and the efforts of the wildlife conservationists are to be taken seriously if we still want the Garden State to be a home for these magnificent creatures.

Here are some great websites to learn about building an osprey platform and how to join the International Osprey Foundation to find out more.

Directions to build an osprey platform: http://www.sancdap.com/osprey/Platform.htm

To look up the International Osprey Foundation on the Web: http://www.sancap.com/osprey/

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