Gloucester, VA, April 5, 2012 — Judging from the nests occupying various man-made structures around Hampton Roads — including cell phone and stadium lighting towers, channel markers and bridges — the osprey has made a resounding comeback in the Chesapeake Bay region.
Osprey populations have been increasing in the Chesapeake Bay region and other U.S. water bodies since the late 1970s, said a Virginia Institute of Marine Sciences spokesman. Osprey populations began recovering in the region following the ban on DDT use in 1972.
Chesapeake Bay is home to the largest concentration of breeding ospreys in the world; the area is the home nesting area to a quarter of the population of ospreys in the contiguous United States, according to the Chesapeake Bay Program. Breeding pairs typically return to the same nest site and remain together for years.
On the Peninsula, osprey populations around Gloucester, and particularly Mobjack Bay, struggled as recently as about five years ago, when many of the osprey chicks were starving due to low food availability, said an expert on the raptors. Bryan Watts, director of the Center for Conservation Biology at the College of William & Mary, said he would like to conduct a follow-up study to the one in 2007 that noted the problems of Mobjack Bay osprey populations.
"Gloucester is doing fine," Watts said. "The whole Mobjack Bay is doing fine."
In the mid-2000s, the ospreys' productivity on Mobjack Bay was fairly poor, Watts said. That was in stark contrast to the James River, where ospreys were doing great, he said.
Part of the problem on Mobjack Bay was likely diet-related. About 70 percent of the ospreys' diet had been menhaden, but by 2007 that percentage had dropped to 26 percent. Ospreys were still bringing in food, but it wasn't the oil-rich, nutrient-packed quality of menhaden, Watts said.
The difference on the James River, where ospreys rebounded from zero in the early 1970s to 500-600 pairs now, is not only the ban on DDT, but also the presence of blue catfish, Watts said. Blue catfish were introduced to the James River in 1968.
Ospreys are "exploiting a resource," Watts said. "They're moving up tributaries into fresher and fresher water."
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