One doesn’t have to spend a lot of time on the water to see the Chesapeake’s ospreys (Pandion haliaetus). Boaters, watermen and even people on land have heard the high-pitched whistle of an osprey surveying the scene from above.
Ospreys thrive around the Bay and are common sights on navigational buoys and markers. There was a time, though, when their survival was threatened.
Twenty to 30 years ago, ospreys in the Chesapeake region faced possible extinction. For years, they and many other birds of prey were unable to produce enough young to maintain their populations. Eggs failed because of extremely thin and easily broken eggshells.
Years of research led to the discovery that a pesticide, known as DDT, caused eggshell thinning in many birds.
Since the ban of DDT in the early 1970s, ospreys, as well as other affected species, have made remarkable recoveries. But a new threat has come to light.
The Chesapeake Bay has some of the finest fishing on the East Coast. In Maryland alone, more than 400,000 anglers ply the Bay and its tidal tributaries from late March through November.
The fishing season also corresponds with the osprey’s breeding season. With approximately 3,600 breeding pairs, the Chesapeake Bay supports one of the largest nesting populations of osprey. At least 1,600 breeding pairs live in Maryland. From March to August, while anglers are fishing the Bay, these magnificent birds are building nests, laying eggs, and feeding and rearing their young.
Ospreys three years or older usually mate for life, and use the same nest site year after year. They migrate to the Bay beginning in March, when the recently reunited pairs will begin the task of nest building or repair.
Ospreys are very tolerant of humans and will fish and nest close to populated communities. They often line their nests with a variety of natural and manmade materials. These materials include paper, plastic rope and fishing line. Some of these prove to be deadly.
While conducting a study to assess what effects contaminants might have on nesting ospreys, biologists from the U.S. Fish and Wildlife Service discovered many osprey young entangled in fishing line or impaled with fishing hooks.
Adults have also been spotted entangled in line. Legs, wings and beaks can become so tangled that the bird will not be able stand, fly or eat. Conservative estimates indicate that fishing line is present in 5–10 percent of all osprey nests on the Chesapeake Bay and surrounding rivers.
The potential for entanglement is high. In Maryland alone there are:
- 44,232 boats registered with a Chesapeake Bay Sport Fishing license
- 417,236 licensed anglers
- Approximately 288 anglers to each breeding pair
- Approximately 144 anglers to each individual breeding osprey
The angler to osprey ratio is probably even higher than what is listed above because a Maryland Chesapeake Bay Sport fishing license covers more than one person for registered vessels.
These figures do not take into account the number of anglers in Virginia’s portion of the Bay.
But you can help. Anglers can reduce the injuries or deaths to ospreys and other wildlife simply by properly discarding fishing lines and hooks. If possible, retrieve broken lines, lures and hooks. Always deposit them in trash containers or take them home. Help protect Bay wildlife.
The resurgence of ospreys after the ban of DDT is a success story. This success can extend to the entire Bay and other wildlife as we continue to protect and restore habitats. With only a bit of effort, we can help to ensure that the osprey remains a familiar sight on Chesapeake Bay.