Backyard Naturalist: Aerial Piracy Offers Unique Chance to View Raptors

Editor’s Note: Outdoors Writer Russ Mohney died Aug. 31. The loss is staggering. His writing and insight into the outdoors of Southwest Washington was unmatched. We will be publishing his popular column each week in the coming months from his abundant body of work created throughout the past decade for The Chronicle. This column was originally published Jan. 28, 2005.
Russ Mohney

I’ve read a number of reports in the past week involving the act of aerial piracy practiced by birds of prey as they steal a hard-earned prize from another raptor.

Right now is a good time to view this common behavior, known as “kleptoparasitism” among birders who enjoy $2 terms. As the number of prey species is reduced by weather or other factors, the bigger birds tend to usurp the catch of weaker predators.

The most recent example I’ve seen was out on the Airport Road, where a pair of bald eagles have been sitting in a cottonwood at the north end of the runway, watching a red-tailed hawk in a snag near the twin silo bases at the dairy farm there.

My friend Bill Wiester called me one recent morning to tell me the older of the two eagles had been watching the activity of the hawk with more than usual interest.

I’d seen all three birds out there on several occasions, but didn’t stop to watch them for any length of time, so I thought it might be worth the investment of an hour or two to see what was happening.

After less than an hour, I watched the hawk detach from its perch and swoop down on something in the short grass of the field surrounding the snag. After a brief struggle, the hawk “hooded” his wings over the quarry, which I assume was a mouse or vole. Almost immediately the adult bald eagle left the cottonwood and buzzed the hawk a couple of times and finally struck it with a talon. I assume the hawk figured it just wasn’t worth the aggravation and flew off toward the river, while the eagle picked up the tiny morsel and carried it back into the cottonwood to leisurely consume it.

I’ve watched this kind of thievery many times, especially between eagles and osprey. Both are pretty good at catching fish, but sometimes one or the other decides to take the easy road and just steal a fish from the successful hunter.

On a lake in central British Columbia, fishing partner Scott Hamilton and I watched an immature bald eagle dip his talons and catch a nice trout — about a 16-incher. He was quickly set upon by a mature osprey that was nesting quite close to the point of encounter. The osprey harassed the eagle until it dropped the fish, which was snatched in midair by the osprey. But the little drama wasn’t over.

Before the osprey could reach its nest, a big mature eagle appeared and struck the osprey in midair — hard — and the hapless fish was again airborne. The eagle snatched it up just before it hit the lake surface and flew away unmolested.

Kleptoparasitism is not at all uncommon and may occur even when prey is abundant. One of the best places to observe the behavior is among the gulls and shorebirds diving on smelt in the Cowlitz this week. When a gull picks a live smelt out of the water, it is usually set upon by every other gull in the neighborhood, and it isn’t at all unusual to see as many as five birds take successive possession of the smelt before one finally manages to swallow it, thereby settling the point once and for all.

When a big predator such as an eagle or osprey attempts to pilfer a prize from another in midair, you are apt to see some of the most intricate flying maneuvers in all of nature. While fishing any of our local lakes this spring, keep an eye on the big predators that are there to share the bounty. You may see this behavior at Mayfield, Swofford, or even Carlisle Lake — and it’s a great addition to your day in the field.
Russ Mohney, a fourth-generation Lewis County outdoorsman, expanded the best of his decade’s worth of “Backyard Naturalist” columns into a book. Copies of “A Simple Song: Recollections from a Backwoods County” are available for $12.99 at Book ‘n’ Brush, the Lewis County Historical Museum and at The Chronicle.