A ban on the use of the insecticide DDT is believed to be the main reason for the rebound in the bald eagle population that began in the latter part of the 20th century. When eagles ate fish, mice and other small animals with DDT accumulations in their bodies, it caused female eagles to lay eggs with abnormally thin shells. When nesting parents sat on the eggs, they often cracked the shells, killing the chicks.
While many of the bald eagles spotted at Hanging Rock continue southward to wintering spots along the Atlantic coast or the Gulf of Mexico, others remain in the region. In a survey last January coordinated by now-retired Pipestem Resort State Park naturalist Jim Phillips, 27 bald eagles were found wintering in Southern West Virginia in and around Bluestone Lake and the southern end of the New River Gorge.
Other recent studies have shown that the West Virginia highlands are a prime over-wintering site for golden eagles living in the Eastern United States and Canada.
"It's been a very exciting year at Hanging Rock," Davis said. "We've had about 2,000 visitors come here to see bald and golden eagles, and the broadwing hawk migration." On Sept. 22, he said, "We had 1,591 raptors fly by, including 182 broadwings in one kettle," or group. "It's amazing to see hawks that look like a swarm of bees, all bunched up and riding a thermal."
On Tuesday, when temperatures plunged to subfreezing levels, Davis ended the days counting shortly after noon, but not before one golden eagle, one bald eagle, 11 assorted hawks and two visitors from Minnesota were spotted at the observatory.
By the end of November, Davis said, he hopes to see the bald eagle tally for the season break the 200 mark and the golden eagle sightings surpass the existing annual record of 54.
"One more really good day with northwest winds will help a lot toward getting us there," he said.
Reach Rick Steelhammer at rsteelham...@wvgazette.com or 304-348-5169.