A dog fight over Woods Bay: Pair of peregrine falcons chase off eagle from a prized perch

This article originally appeared in the Daily Inter Lake in 2004. View published clip (PDF).

Something was wrong: the falcon aerie was eerily quiet.

Byron Crow, field project coordinator with the Montana Peregrine Institute, put his binoculars to his eyes to observe a golden eagle perched in a tree on a cliff top.

“That’s a bad sign, because he’s up there eating something,” he said.

That something could be one of the two peregrine falcons Crow had hoped to find. It was the second week of April; the pair should have returned the previous week.

He spoke into his microcassette recorder: “An adult male golden eagle is on the perch tree. Either we have a problem, or the falcons have not returned and are not defending this cliff.”

This 300-foot cliff, less than a mile northeast of Woods Bay, contains one of the oldest known and most productive peregrine falcon aeries, or nests, in Montana. The nest sits about 80 feet below the perch tree, above a ledge and in a vertical crack on the rock face.

Crow was somber. He had first visited this site with Jay Sumner, founder of the institute, in 1999. Crow had never before seen a peregrine falcon, but when he did that day he was “blown away, right then and there.”

“That’s when I knew wildlife biology and raptor research was going to be my bag,” he said.

Crow pocketed his recorder and resumed hiking up toward the tree to verify what the eagle had been eating.

He paused to watch turkey vultures drift in from Woods Bay.

Suddenly, screams shattered the stillness. Two agitated peregrine falcons swooped in from the north, heading straight for the intruding eagle.

Crow whooped. “Thank god, they must have been out hunting,” he said, lifting his binoculars to watch the two birds defend their territory.

The female falcon, larger and more aggressive than the male, attacked first. She pitched, rolled and dove toward the much larger eagle. It held steady as she veered away, letting her mate stage his first attack as she repositioned to stage her second.

A flying falcon maneuvers like a fighter jet. While hawks and eagles effortlessly soar on broad wings while hunting, a falcon’s svelte wings propel it from perch to prey at speeds estimated to be 180 to 230 miles per hour.

“The prey absorbs all that energy,” Crow said.

Knocked out of the air, the victim, often a duck or a shorebird, essentially dies of blunt force trauma.

The falcons weren’t trying to kill the eagle, however; they just wanted to let it know it wasn’t welcome.

The eagle soon got the hint and launched off the branch with a stretch of its massive wings.

If a falcon is like a fighter jet, then an eagle is like a heavy bomber: powerful, but lumbering during takeoff and not as agile once in the air.

But a golden eagle, unlike a bald eagle, which Crow said is likely to just fly away, often will attempt a counterattack when provoked.

And, Crow said, the golden eagle is one of the few natural enemies of the peregrine falcon. “A golden eagle or great horned owl can take them perched, but nothing can take them on the wing,” he said. “They’re the fastest bird in the air.”

The eagle headed straight for the female falcon — which deftly avoided the eagle’s outstretched talons — before disappearing around the corner to the east of the cliff.

Both falcons pursued.

The air was silent for a moment until the female returned to her perch atop the tree. Her tree. “She’s screaming her dominance,” Crow said.

The male returned shortly, flying a sortie to check out Crow before landing on a branch below his mate. His cries joined hers.

The eagle was gone.

Crow originally had planned to hike up to the cliff top and himself draw out the falcons; the signs he needed of an active aerie were the presence of both birds, and for them to defend their space. But the eagle had done Crow’s work for him.

“Driving off that golden eagle has them stressed,” he said. “There’s no point in bothering them further. We know they’re here.”