I wish I had more time to spend on and around the water. I love to watch the ospreys patrol the skies in search of fish. Some people call them sea-eagles or sea-hawks. In many places, ospreys can only be observed during certain parts of the year, but here in eastern North Carolina they live here year-round.
Forty years ago, sighting an osprey was rare. They faced the same decline as the bald eagle and many other predatory birds. Certain pesticides didn’t break down in the environment very fast. DDT is the one everyone talks about, but there were others.
These chemicals accumulated in the bodies of animals. Those at the top of the food chain became the most contaminated because of a phenomenon called biomagnification. Plants and insects were sprayed and whatever ate them also absorbed the poison. Animals couldn’t rid themselves of these toxins, which became more concentrated. The same thing happened with mercury levels of swordfish and other apex predators in the ocean.
Since about 1970 we have done a much better job reducing chemical contamination of our environment. Eliminating lead in gasoline means there is now far less lead in our air and waterways.
Pesticides and other chemicals never really killed many ospreys. They caused females to lay eggs with thinner eggshells, and the birds were unable to roll and incubate the eggs without breaking them. Therefore, reproduction suffered greatly.
I’m glad their populations have recovered. It’s fun to watch them. These raptors can fly at speeds as fast as 80 miles per hour. They wait until all odds are in their favor. Then they do their thing.
Ospreys are efficient fishermen. Ask any aquaculture farmer and they will tell you that ospreys can steal profits in a hurry. Killing them isn’t an option as they are protected. Harassing them or interfering with their nests isn’t allowed either.
When ospreys catch fish, they position their prey facing forward for better aerodynamics. This is important as these birds carry large payloads for their size. Ospreys look larger, but adults only weigh about three pounds.
Ospreys nest in large elevated open places near water. They build structures bird watchers can monitor with ease. Both males and females help build nests from sticks. They line them with finer materials.
Parents use the same nests year after year and fortify them with more material. After several years these structures become massive. Sometimes nests are constructed at the tops of large dead trees, but utility poles and other man-made structures become the basic framework for many osprey nests.
Females usually lay three eggs which hatch in five to six weeks. Sometimes males help incubate them. Once the eggs hatch, males bring fish back to the nest. Young birds stay in the nest with their mother for about two months.
Older hatchlings usually bully the younger ones when food is scarce. Often, only the first hatched egg survives. Ospreys only hatch one brood per year, so a productive nesting site is critical for survival of the young. Ospreys are long-lived birds and usually breed for about ten years.
Ted Manzer teaches agriculture at Northeastern High School (firstname.lastname@example.org).