Hi Tim:

It happens a lot, under the right circumstances - If you're bigger, stronger, etc. than the bird that caught the prey, it's then easier to rip off the other bird than to spend time and energy catching it yourself.

Over ten years ago, there was a project tracking a radio-tagged adult female gyrfalcon on the Samish Flats; she regularly ripped off harriers. The observers were keeping score, and the harriers' collective score was 0. I think the gyr's score was 20-something.
..
Maybe five or six years ago, I was at the West 90 leading a field trip. An adult female peregrine descended from a power pole toward the flooded fields and, with a big splash, snatched a female bufflehead out of the water. Within seconds, four sub-adult bald eagles had converged on the peregrine and dispossessed her of the duck. The last view of the eagles was the quarrelsome foursome heading over the dikes with an adult bald eagle barreling through the air in apparent pursuit, while the peregrine returned to a power pole to watch and wait for the next opportunity.

About two or three years ago, a friend and I watched at close range when an adult female gyr ripped off an adult male harrier near Thomas Rd. No matter how much the lovely little male twisted and turned, the gyr was always above him, controlling him. She was so bulky that it was like watching a sumi wrestler against a bantam-weight or some similar mismatch. I kept hoping the harrier would somehow fly away and escape, but I knew it was no use - gyrs are extremely fast. The harrier eventually relinquished the vole; it took the gyr only a few seconds to gulp it down.

The technical term for this is kleptoparasitism - less technical term is piracy. It's common with raptors and seabirds (classic example seen on the Sound in the fall is jaegers ripping off Bonaparte's gulls). It's always a thrill to watch, though I can't help but feel some sympathy for the bird that gets ripped off.

Ruth Taylor
Seattle/Ballard
rutht at seanet.com
-----Original Message-----
From: Tim O'Brien <kertim7179 at centurytel.net>
To: Tweeters <tweeters at u.washington.edu>
Date: Saturday, February 15, 2003 9:35 PM
Subject: bald eagle steals a prize


Greetings Tweets,

Today, I saw something that quite surprised me. I was birding along the Wenzel Slough Rd., west of the twin silos near the area where the road floods, when I'm observed a female Northern Harrier on a post. After watching the harrier for a little while, it took off and coursed over the field in search of prey. It didn't take long for the harrier to find something, she proceeded to swoop up and hover for a few seconds and then dive down into the grass. The harrier came back up with a small mammal in its talons. She flew a short distance away and landed back into the tall grass to devour her catch.

All this time, I had been ignoring a mature Bald Eagle that was perched in a tall spruce tree that I had spotted before the harrier. Suddenly, while my binoculars were focused on the tall grass where the harrier had landed, the Bald Eagle swooped in and dropped right in on the harrier. I wasn't paying attention when the eagle flew in, but on its way it had flushed several ducks and one Great Blue Heron out of a watery area of the field which filled the air with the sounds of panic. The harrier came flying up out of the grass empty handed. About 30 seconds later, the eagle arose from the grass with the harrier's prey in its talons. The eagle flew right back up to the same spot on the spruce tree where I had first spotted it. The harrier flew off to another post.


Tim O'Brien
Elma, WA
mailto: kertim7179 at centurytel.net