DULUTH, Minn. (AP) — Broad-winged hawks are the most common raptor at Hawk Ridge. Bald eagles are the biggest. Sharpshins come through by the hundreds early each fall.
But northern goshawks, the fierce hunters of the boreal forest, are the signature raptor of Hawk Ridge Bird Observatory in Duluth.
"They're Hawk Ridge's claim to fame," said count interpreter Erik Bruhnke. "People come from all over the world to Hawk Ridge to see the goshawk numbers."
None of the other hawk observation sites across North America get as many goshawks as Hawk Ridge does, said Frank Nicoletti, banding director at Hawk Ridge.
"This has always been known as the best goshawk spot in the world," Nicoletti said.
Thousands of visitors will flock to Hawk Ridge this fall, many of them converging for the annual Hawk Weekend, coming up Friday through Sunday. They'll see plenty of sharpshins and broadwings and many other species of hawks. Some goshawks may be among them, but the Hawk Ridge faithful know the cool days of October will bring the greatest numbers of these big, powerful hunters.
"They're pretty much daily through the month of October when the migration is peaking," Bruhnke said.
About 200 to 300 come through each fall, Nicoletti said. Last fall, he and fellow banders caught and banded 159 goshawks, the Duluth News Tribune (http://bit.ly/1brDozW ) reported.
Northern goshawks are birds of the boreal forest. They're the largest of the raptors known as accipiters, birds with short, rounded wings and long tails, designed to maneuver with agility through the aspen parklands they call home.
They prey on ruffed grouse and other large birds, as well as snowshoe hares. In her book, "For the Birds," Duluth's Laura Erickson calls the northern goshawk "the fiercest bird in the world." Visitors to the canoe country will often hear the high-pitched "kye-kye-kye" shrieking of a goshawk if they get too close to its nest. Goshawks are known to attack humans and animals that venture too close to their nests, according to the Cornell Laboratory of Ornithology.
Goshawk numbers at Hawk Ridge can vary widely. In so-called "irruption" years, goshawks short of prey in the North will move through Duluth in large numbers as they seek food sources, Nicoletti said.
It was the chance to see goshawks that drew Nicoletti to Duluth originally in 1991. He had planned to see and band the birds during their irruption years at that time and then move on. But he decided to stay.
Goshawk irruptions typically have occurred every nine to 11 years, he said. The last irruption years at Hawk Ridge were 2001 and 2002, Nicoletti said.
"We're actually due for one right now," he said. "I saw signs of it last year, toward the end of the season. But there's still no real indication it's coming."
Irruptions are not as pronounced or predictable as they once were, he said.
"We don't know why the cycle may not occur anymore," Nicoletti said. "It's not occurring in the numbers it did in the '70s and '80s and '90s. It seems to be declining."
Regardless of their numbers, every goshawk banded and released at Hawk Ridge is an occasion. Naturalists at Hawk Ridge hold raptors and educate visitors about them before the birds are released. Holding a goshawk is often an auditory experience, said Gail Johnejack, education director at Hawk Ridge.
"They're the loudest," Johnejack said. "The goshawk is always attentive and shrieks, saying 'I'm somebody.' "
"I've held quite a few," he said. "They're very feisty. They're pretty uptight birds. They're just unhappy about being held."
They're also an especially handsome bird, up to two feet long with a wingspan of more than 40 inches. Immature goshawks are brownish, but adults are gray with striking red eyes.
Perhaps this will be the irruption year Nicoletti and others at Hawk Ridge have been waiting for.
Information from: Duluth News Tribune, http://www.duluthnewstribune.com