Tracking raptors on the coast
Every fall, ospreys, falcons, eagles, hawks and other raptors migrate through the Chesapeake Bay region on their way to warmer places. And as they do, groups of volunteers keep track of them as part of the Hawk Watch initiative - an international effort to study raptors during their migratory period.
There is, for example, Jen Ottinger, who keeps her binoculars fixed on the sky from a perch at Cape Henlopen State Park in Delaware. She has participated in the Hawk Watch, which runs from September 1 to November 30 ever year, since 1995. And she says she can see hundreds to thousands of birds in a single day - including raptors.
"I’m a total raptor enthusiast," Ottinger says. "I love studying raptors; I’ve been all over the US doing raptor surveys, and migration is amazing because you can see 15 different species of raptor in one day."
Ottinger and her fellow Hawk Watchers focus on recording the number and types of raptors passing through their region and they feed that information into a universal population database.
When she scans the sky, she looks for wing shape, size and flapping style for clues as to what raptors are flying by. And she has a few other clues, as well.
For starters, the birds need to be moving "southerly with purpose," she says.
"You can tell by their behavior.They’re on a mission; they’re trying to get somewhere."
Ottinger and the hawk watchers also help identify trends as they log two defined pathways in the Chesapeake region: Coastal migration and ridge migration. Adult raptors tend to take the ridge path through the mountains of Western Maryland, while the younger ones—typically less than a year old—drift east and fly along the coast.
Dave Brinker, an ecologist with Maryland’s Department of Natural Resources, says younger birds "don’t know the geography as well" as the older ones.
Sure, migration is "hardwired into them genetically," he says. But they "get blown away from the best places to migrate like the mountain ridges, and they drift onto the coastal plain."
But while ecologists may understand why young raptors head toward the coast, Brinker says they don’t know the precise path these raptors are taking. That’s why they need hawk watchers spread throughout the region.
"You can’t have a big database if you only just have a few sites," explains Brian Taber, president of the Coastal Virginia Wildlife Observatory.
Taber, who heads up the Kiptopeke Hawk Watch on Virginia’s Eastern Shore, says the data gathered over a number of years will help define the migratory paths and inform future conservation management decisions.
"The more sites the better, the more data points the better," he said. "And when you have statisticians take all that data to try to analyze it, the more you have, the more accurate your information is going to be."
Tracking these young raptors’ coastal paths could also be valuable as states examine building offshore wind farms.
When NRG Bluewater Wind began planning for a wind farm off the coast of Delaware, state wildlife biologists began collecting data to see if raptors and wind turbines could co-exist.
Kate Fleming, one of the biologists, said they "started collecting flight height information to help answer that question."
But NRG’s plan fizzled in 2011 due to lack of funding. And Fleming says they didn’t collect enough data to draw any conclusions. In fact, it could take years to gather enough data to fully understand the potential impact of wind turbines on raptor migration, she said.
That information could become necessary, as NRG Bluewater Wind still holds a federal lease on offshore ocean bottom and could try again.
Meanwhile, USWind, a subsidiary of the Italian firm Renaxia, holds a lease on 125 square miles of federally owned ocean bottom on the outer continental shelf about a dozen miles off Ocean City, MD. Hearings on the company’s application for Offshore renewable Energy Credits begin next week before Maryland’s Public Service Commission and are expected to continue into May.
That means the Hawk Watch volunteers will keep heading out each fall to gather this kind of information -- as they enjoy watching their feathered friends in flight.
Chesapeake: A Journalism Collaborative is funded with grant support from the Clayton Baker Trust, The Bancroft Foundation, Michael and Ann Hankin, The Jim and Patty Rouse Foundation, The Rob and Elizabeth Tyler Foundation, and the Mid-Shore Community Foundation.