They might be in trouble and they might not. No one knows for sure.
That’s the problem.
It’s one researchers are trying to solve, though, with the help of hunters, hikers, birders, backcountry anglers, falconers and pretty much anyone else who roams the woods.
The ornithological committee of the Pennsylvania Biological Survey – a collection of scientists and wildlife managers focused on birds – is looking to determine just how many northern goshawks exist in the state and where.
That’s easier said than done.
Goshawks – an accipiter, meaning a hawk with short, broad wings and relatively long legs, adapted for flying in forests — are native to Pennsylvania. They prey on squirrels, larger birds like blue jays and crows, chipmunks and the like.
They’re hard to keep tabs on, though.
Some raptors, like ospreys, readily nest around people, said Doug Gross, the Pennsylvania Game Commission’s endangered and non-game bird section supervisor. About 90 percent of the 149 known osprey nests in Pennsylvania are on man-made structures.
Photo: US Fish and Wildlife Service
“Goshawks are just the opposite. They’re a deep forest species. They avoid people,” Gross said.
“It’s a real mystery bird.”
That’s long been the case.
Pennsylvania once, in the early 20th century, paid a bounty for every goshawk killed, said Chelsea DeMarco, a graduate student at Penn State University working on the project. That, she said, indicates they were at least fairly common.
No one ever tried to count how many were on the landscape, though.
“So we don’t really have any numbers to compare to,” DeMarco said.
There are some indications populations have declined, however.
Two breeding bird atlas surveys – attempts to identify which birds were nesting in the state and in what numbers – were conducted in Pennsylvania. One took place from 1983 to 1989, the other from 2004 to 2009.
Goshawk reports declined nearly 28 percent from the first to the second, DeMarco said.
Similar declines are suspected of occurring in New York, while the birds have already vanished from Maryland and West Virginia, said Laurie Goodrich, director of long-term monitoring at Hawk Mountain Sanctuary, an eastern Pennsylvania raptor research center.
Fewer goshawks are showing up in migration counts at Hawk Mountain, too, she added.
Some think that might be more indicative of a behavioral change than an actual population drop. Goodrich noted that, similarly, fewer migrating red-tail hawks are being counted recently as birds stay within the state year-round given milder winters.
“But that doesn’t explain why goshawks aren’t here in the summer,” Goodrich said.
There are theories as to what’s going on, Gross said. They range from habitat loss due to energy development and suburban sprawl to disease related to West Nile virus.
Definitive answers are few, though.
“It just seems like there’s a lot less out there,” Gross added.
To pin things down, DeMarco has been training volunteers to look for the birds, with a goal of establishing a baseline population. That’s a two-year-effort.
This first year’s focus is on surveying the state’s 160-plus historical goshawk nest sites, DeMarco said. They’re sites to which birds have shown great loyalty.
“You can almost draw a one kilometer circle around an old goshawk nest, and about 90 percent of the time there should be birds within that area,” DeMarco said.
“They may not be the same birds, and they may not be in the same exact tree, but there’s something in that area that keeps bringing birds back year after year. Some of those areas might have birds for 30 years.”
There are no guarantees with elusive goshawks, though. A few weeks into looking, DeMarco admitted, volunteers haven’t counted any.
Now is the time to be seeking them, though.
Goshawk reports collected at any time of year have value, Goodrich said.
“But once we get into July and August, the birds do move around a little bit, so it’s hard to pin them down to a nest site,” Goodrich said. “So right now, from April into May and June, is really prime because birds are still tied to their nest site.”
There are about 300 bald eagle nests in Pennsylvania, Gross said, along with 149 osprey nests.
Yet, if he had to guess, he’d put the number of nesting goshawk pairs at less than 100.
That, he said, seems low.
The birds were likely never superabundant, he added. A single pair will have a home range of about two square miles, so they don’t like close neighbors, even among their own kind. But Pennsylvania has a lot of forest, he noted.
“We think the habitat could support more. We’re not sure why it isn’t,” Gross said. “We’re trying to figure that out.”
Also unclear is why the birds aren’t where they once were.
The first breeding birds atlas listed goshawks in places like Westmoreland, Somerset, Huntingdon, Mifflin, Juniata and Dauphin counties, Gross said.
“I don’t know if we have any, maybe one or two, south of Interstate 80 anymore,” Gross said. “So it’s not just the numbers, but the distribution, that’s changed for this species.”
Clearly, there’s a lot to learn.
“Most of the things we say about this species, it’s based on a pretty small sample size. And a lot of this data we have comes from the West,” DeMarco said.
This new survey is meant to change that. The birds deserve it, Gross said.
“They’re a very wild, very cool bird, one that’s been coined the ultimate forest raptor,” he said. “They’re a great representative of wilderness in eastern forests.”
Get involved with goshawks
The effort to monitor northern goshawks in Pennsylvania is largely a volunteer one.
“We really need to rely on bird watchers, hunters, hikers and other people out in the woods to report back on what they’ve seen,” said Hawk Mountain’s Laurie Goodrich.
So how to get involved?
Would-be volunteers interested in getting training and/or going out with other monitors can contact project coordinator Chelsea DeMarco at firstname.lastname@example.org or at 585-519-1596.
More details, including information on how to report sightings on your own, can be found on the Pennsylvania Biological Survey website at www.pabiologicalsurvey.org/goshawk/. It details how to identify goshawks and their nests, has a recording of a goshawk call, and offers report forms, t-shirts and more.
And in the meantime, volunteers need not worry that by reporting a nest site they’re putting it at risk either. That’s been a concern for some.
“It’s all as confidential as the people sharing the reports want it to be,” said DeMarco.