She is one of 25 official "compilers" who have been counting raptors, or taloned birds of prey, since Sept. 4 as part of the Militia Hill hawk watch at Fort Washington State Park in Upper Dublin Township.
Marylea Klauder of Oreland organized the watch in 1987 when she noticed that the Militia Hill area provided a spectacular view of the migrating birds. Each year since, for 88 straight days from early September through November, the volunteer compilers and hundreds of regular folks have chronicled their sightings of hawks, falcons, ospreys, vultures and eagles, she said.
"Fifteen years ago, it was thought that you could only see raptors migrating on the coasts or the mountains, so this seemed fairly unique," she said. "And I wanted to bring the park to the attention of the community."
In 2 1/2 weeks this year, the birdwatchers on Militia Hill have already registered about 6,000 sightings, Klauder said, including eight bald eagles.
About 80 percent of the sightings recorded so far have been broad-winged hawks, whose migratory period usually begins in early September. More than 12,000 raptors of 17 species were counted and identified last year, according to Klauder. The numbers are reported to the Hawk Migration Association of North America, headquartered in Hilltown, N.Y. The group compiles migration statistics nationwide.
Scientists aren't sure why migrating birds, many of which come from Canada and are en route to South America, frequent a particular area. But it is known that smaller raptors such as hawks travel using thermals - updrafts of hot air.
Some environmentalists theorize that the heat radiating from the concentration of highways in the area, including Route 309 and the Pennsylvania Turnpike Extension, causes a lot of updrafts, according to Tom Laura, regional editor of the Hawk Migration Association newsletter.
