Volunteers count raptors migrating south

May, the hawk watchers count the birds on their northern migration. August to Thanksgiving, they lean back on folding chairs watching the sky and counting the birds flying south. Sometimes the watchers are joined by visitors, who are welcome when Audubon members are present. On the site, a couple of handmade log benches were built with reclined backs for easy sky watching. On poles, weather gauges spin. At the top of one pole are a leafy branch and a mounted owl decoy.

“Hawks and owls don’t get along,” said Mr. Wargo. “Sometimes hawks will come closek, squawking at it. Sometimes they attack it.”

Among raptor watchers, Allegheny Front Hawk Watch is known for the large numbers of golden eagles that pass during spring and fall migrations.

Waiting for hours — days — on top of a mountain with his neck craned and eyes studying the sky is a vocation Mr. Wargo takes seriously.

“It’s citizen science, This is important research we’re doing. It’s vital,” he said. “We count and identify the species as they pass here, and other groups document them at other sites.”

Data collected at Allegheny Front Hawk Watch will be uploaded to web registries for ornithologists to merge data from 300 hawkwatch sites in North and Central America.

“They use it for population counts,” said Mr. Wargo. “If counts of a specific species are down, they try to find the cause. Sometimes raptor populations fluctuate naturally based on cyclical populations of food sources. Sometimes the change is not due to natural causes, and that’s something we can change.”

Wrapped from boots to hoodie in brown winter outerwear in September, Mr. Wargo occasionally glances to the sky as he speaks.

“I have clicker counters in each of my pockets. My front right pocket says BW, that’s broad wings [broadwinged hawks] — eight so far this hour. Left top pocket is red tails [red-tailed hawks] — there’s the two that you just saw and an earlier one. In the lower pocket I have my eagle counter — we don’t have an eagle so far this hour, and sharp shins [sharp-shinned hawks] — I don’t have any this hour.”

When multiple birds pass, individual group members responsible for specific swaths of sky call out the species and number. It’s been a slow morning. At times, said Mr. Wargo, the group records the passing of thousands.

He reaches into a pocket and clicks a counter as he steps up to a picnic table, neatly covered with a red and white checkered cloth, to transfer clicker counts to the hawk watch sheet.

“We take our environmental data — wind speed, temperature, direction and humidity — we record all that and tally up our birds,” said Mr. Wargo. “So far today we have four bald eagles — one was a secondyear eagle, one was a juvenile, one was a subadult, and another was a juvenile. We have two osprey and a northern harrier, nine sharp-shinned hawks, four Cooper’s hawks, 24 broadwinged hawks and nine redtails. I’ll add the new data from this hour.”

Suddenly, from the line of folding chairs behind him, hawk watchers gasp and point as a lone bald eagle circles above, riding the updraft and momentarily watching the watchers. No optics are necessary: mature eagle, white head and tail, no white body and wing feathers that would identify it as a subadult.

Mr. Wargo reaches into a pocket and clicks a counter.

Learn more about hawk migration and how they’re counted at www.hawkcount.org.

For information and visiting details go to www.alleghenyplateau-audubon.org/ hawk-watch.php.