Article

Ferruginous hawks in decline

Jason Lowe, a biologist with the Bureau of Land Management's Eastern Washington office in Spokane, ...conducted two field surveys this spring and summer, which confirmed what he feared: The hawks are fewer and farther between. Where there were 17 nesting pairs in 1987 in the Juniper Dunes area of Franklin County, only four were spotted last year and just one this year. ...Wind farms are proliferating in Southeast Washington and Northeast Oregon, which is a concern, he said. "Information is not complete, but there have been reports of hawks being hit by the (rotating windmill) blades," he said. While ferruginous hawks are unlikely to nest on ridges where windmills are located, they typically forage for food over a 17-mile radius, and that can include wind farms.

JUNIPER DUNES -- Sneaking up on the nest of a ferruginous hawk begins about a half-mile away. Alert and sharp-eyed, the largest raptor in the hawk family is wary of intruders and will flush without warning.

So Jason Lowe, a biologist with the Bureau of Land Management's Eastern Washington office in Spokane, advanced carefully through the Juniper Dunes while scanning the clear desert sky for anything on the wing.

His target was a 40-foot tall juniper tree known to have harbored a hawk nest for several years.

There was an urgency for Lowe in stalking these raptors. Ferruginous hawks, a threatened species in Washington, are at their lowest counts since field surveying began 30 years ago, he said.

And one state raptor specialist said further population declines could force wildlife officials to request that ferruginous hawks be classified a state endangered species.

The hawks, which can be mistaken for an eagle because their wingspan can reach 4 feet or more, prefer the desert and open grasslands. Jackrabbits and small mammals like ground squirrels make up their diet, so the Mid-Columbia shrub-steppe offers ideal nesting territory.

But studies indicate that habitat is declining, along with... more [truncated due to possible copyright]  

JUNIPER DUNES -- Sneaking up on the nest of a ferruginous hawk begins about a half-mile away. Alert and sharp-eyed, the largest raptor in the hawk family is wary of intruders and will flush without warning.

So Jason Lowe, a biologist with the Bureau of Land Management's Eastern Washington office in Spokane, advanced carefully through the Juniper Dunes while scanning the clear desert sky for anything on the wing.

His target was a 40-foot tall juniper tree known to have harbored a hawk nest for several years.

There was an urgency for Lowe in stalking these raptors. Ferruginous hawks, a threatened species in Washington, are at their lowest counts since field surveying began 30 years ago, he said.

And one state raptor specialist said further population declines could force wildlife officials to request that ferruginous hawks be classified a state endangered species.

The hawks, which can be mistaken for an eagle because their wingspan can reach 4 feet or more, prefer the desert and open grasslands. Jackrabbits and small mammals like ground squirrels make up their diet, so the Mid-Columbia shrub-steppe offers ideal nesting territory.

But studies indicate that habitat is declining, along with the hawk population.

Lowe conducted two field surveys this spring and summer, which confirmed what he feared: The hawks are fewer and farther between.

Where there were 17 nesting pairs in 1987 in the Juniper Dunes area of Franklin County, only four were spotted last year and just one this year.

"The biggest problem is loss of habitat," Lowe said as he led the way along a dusty ranch road toward that single known hawk nest.

While expansion of agriculture makes the hawks retreat to undeveloped territory, the intrusion of motorized recreation -- such as motorcycles and all-terrain vehicles -- into the dunes also has disturbed the birds.

"But it's not just ATV activity. I think (the hawks) are declining overall, even where there aren't ATVs," Lowe said.

The 30-year history of surveys in the dunes shows ferruginous hawks are far from well-established.

There were six nesting pairs in the dunes in 1977, which dropped to a low of one pair in 1983, followed by the highest count in 1987 with 17 nesting pairs. Since then the average had been five to six pairs, with the lowest numbers in the last decade.

The declining counts sparked the BLM to step up efforts in Juniper Dunes to protect hawk habitat in March of this year.

"We've instituted emergency closures in areas that used to be open to ATVs because of the past historical use by the hawks," Lowe said.

He explained that the ATVs erode the soil, create noise and destroy plants that attract squirrels and kangaroo rats the birds depend on for food. Private property with planted fields nearby does help buffer the protected zones for the birds.

Lowe stepped carefully to not surprise a rattlesnake, walking through knee-high brush bristling with tens of thousands of Mormon crickets, a flightless katydid up to 3 inches long. The insects are of little nutritional value to the hawks, whose preferred prey is small mammals.

Lowe believes a decline in jackrabbits in the Mid-Columbia may be the biggest reason for the decline in ferruginous hawks, rather than current human activities. He explained that efforts by farmers to eradicate the rabbits in the 1920s, 1930s and 1940s were so effective that they are seldom seen anymore.

Mike Livingston, district wildlife biologist for the state Department of Fish and Wildlife, said restoring this food source to historical levels in the hawks' nesting territories could be a good way to help increase their population.

"Unlike their cousins, the red-tail hawk, ferruginous hawks are not as adaptable," he said.

Lowe worked his way entirely around the juniper, which was standing alone on a small rise, straining through his binoculars to spot the nest or adult ferruginous hawks.

But there were no adults, which apparently were off hunting. Instead, he spotted two young hawks about 6 weeks old and already beginning to fledge. Even as juveniles, they were larger than most other birds.

"These chicks are bigger than the ones here last year. They are looking very healthy and well-fed," Lowe said as he watched them.

Later that day, he checked another known nesting site but found it unoccupied. Finding only one nest in the Juniper Dunes this year was disappointing to Lowe because that has happened only once before since 1977, in 1983.

Livingston said statewide surveys for ferruginous hawks were started in 2004 because of concerns about the dropping population and loss of habitat.

Benton and Franklin counties offer prime areas for the hawks in Washington, and the fact that both counties have experienced steady growth over the past decade makes matters worse for the birds, Livingston said.

And now, he said, the hawks are having to compete for air space.

Wind farms are proliferating in Southeast Washington and Northeast Oregon, which is a concern, he said.

"Information is not complete, but there have been reports of hawks being hit by the (rotating windmill) blades," he said.

While ferruginous hawks are unlikely to nest on ridges where windmills are located, they typically forage for food over a 17-mile radius, and that can include wind farms.

One bright spot for the birds has been the federal Conservation Reserve Program, Livingston said. That program pays property owners to not plant former agricultural lands and keep them in their natural state to prevent erosion and preserve wildlife habitat.

Still, the long-range picture for ferruginous hawks is iffy at best, said Jim Watson, a raptor research specialist with the state Department of Fish and Wildlife who is based in Concrete.

"It isn't doing very well in Washington, and the decline is pretty evident in the Mid-Columbia," Watson said.

"If it declines further, we'd recommend putting it on the endangered status," he added.

Madonna Luers, a spokeswoman for Fish and Wildlife, said when an animal is placed on endangered species status, it means officials have to take a closer look whenever there are decisions involving land use and planning that could affect the animal.

"We have to consider nesting issues, for example," she said. Being a state endangered animal also makes it against the law to kill, harm or harass the animal, Luers explained, although raptors already are protected under federal law.

But state officials do not have authority to close an area that includes a state endangered species, she said.


Source: http://www.thenewstribune.c...

AUG 16 2009
http://www.windaction.org/posts/21769-ferruginous-hawks-in-decline
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