Observatory For The Birds Oregon Station Keeps Track Of Migrating Raptors, Prime Indicators Of Ecosystem’s Health

Data collected by volunteers have helped wildlife officials track the population of migrating hawks from Alaska to South America, and one of the busiest stations is in Oregon.

Bonney Butte near Mount Hood, one of 13 HawkWatch International counting stations throughout the West, routinely logs 100 or more raptors a day as birds fly south during the fall.

In its 11 years of operation, Salt Lake City-based HawkWatch has counted 400,000 of the birds, which are vital indicators about the health of the environment because they are at the top of the food chain.

The public is welcome to visit spotters at the 5,600-foot-high Bonney Butte station, atop a 35-mile-long ridge just a few miles east of Mount Hood.

But a banding station is off-limits to the public to keep distractions to a minimum for both birds and volunteers, who use nets to grab the raptors out of the air.

“We haven’t injured any birds during the banding process,” said Carole Hallett, a longtime volunteer. “I suppose there’s always the potential, but we’re a small operation.”

Just in case there is an injury, Hallett is licensed as a bird rehabilitator and knows how to give avian first aid. Even pigeons, which act as lures during the banding process, receive loving care.

“Pigeons are pretty hardy,” Hallett said. “I raise all the birds myself. When a red-tail hit one of my birds on the wing, I retired it for the season even though it was a minor injury. Some of my pigeons have been working for me for four or five years.”

When Hallett traps a hawk, the bird usually is held captive for less than five minutes while measurements are taken. A tally sheet is used to record the size of the bird’s beak, the length of its longest talon, its wing and tail and the amount of fat along its breast bone.

“The birds usually sit calmly in your hand while you take caliper measurements to a hundredth of a millimeter,” Hallett said. “I don’t know why they’re so calm. It might be because they are conserving energy or maybe planning ways to get you or to escape.”

A metal band with a number and address is placed on a leg.

“I was totally hooked the first time I saw a bird being banded,” Hallett said.

Paul Grinrod, a HawkWatch research assistant based in Salt Lake City, said data compiled during the first 10 years of HawkWatch found populations of red-tailed hawks, peregrine falcons, merlins, ospreys and turkey vultures to be on the increase.

But golden eagles and northern goshawks were found to be diminishing.

“Raptors are indicators of the overall health of an ecosystem,” Grinrod said. “If raptors disappear, you have to assume there is a bigger underlying problem.”

The U.S. Fish and Wildlife Service relies on its own research, as well as programs such as HawkWatch, to determine whether to list a species as threatened or endangered under the Endangered Species Act.