Urban Fish Hawks Get Medical Checkup

Eating goldfish could be part of the problem

Scientists studying impact of contaminants on fish-eating birds

Lazarus and Barnett A. Rattner, a veteran scientist with the U.S. Geological Survey's Patuxent Wildlife Research Center, have been paying "nest calls" every 10 days or so since March on all the ospreys in Back River. They're trying to figure out why the "fish hawks," as they're sometimes called, aren't doing so well there.

Ospreys thrive across much of the Chesapeake Bay region. They have rebounded since the banning in the 1970s of DDT and other pesticides blamed for hurting reproduction of many raptors, including bald eagles. The last baywide osprey survey, in the 1990s, put the population at 3,500 nesting pairs, but that number has likely grown to 6,000 or 8,000, said Bryan D. Watts, director of the Center for Conservation Biology at the College of William & Mary.

Osprey with Houndfish

"They've really exploded," Watts said, "and their distribution has changed. They've moved more inland than they were historically."

But even as ospreys spread up other bay tributaries, there seem to be relatively few nesting on Back River and in heavily urbanized waterways such as Baltimore's Inner Harbor and Washington's Anacostia River.

The scientists' Back River visits are part of a larger study, now in its second year, investigating whether ospreys' health and reproduction are being affected by past and continuing pollution. The team also is checking nests in the Susquehanna, Potomac and James rivers, as well as in Baltimore harbor and the Elizabeth River in Norfolk, Va. — two of the bay's toxin-laced "regions of concern." The researchers monitor the nests to see how many eggs are laid and how many hatch. They also take blood samples from the chicks, and the occasional egg, to check for chemical contaminants.

Maybe they just don't live around the dirty spots because they're noisy, smell bad, and the fish taste awful.