A couple of weeks ago, Floyd Tomkins sent a message to the Sitka birds e-mail list with an interesting observation. I asked for his permission to post it to my weblog in case others have additional insight into what was going on.
This past Saturday, a ball of baitfish or similar prey got trapped at the surface in about the middle of Thimbleberry Bay. Gulls were first on the scene, followed by increasing numbers of eagles. The eagles began with the usual swoop and grab attack, then tried to hover. Finally, they began dropping down into the water and staying there for a while before taking off from the surface.
At one point, one immature and five adult eagles were floating in the water, head and back above the surface and wings partially spread in front of them. They would stay there for five or ten seconds, looking not a little ridiculous; then, by raising their wings high enough, they could heave themselves into the air and resume flying.
I’ve never seen this behavior before. What are they doing—grabbing blindly below the surface? Hunting seems the likeliest and perhaps only explanation, but how does it work?
Floyd noted to me that he subsequently heard from someone who had recently observed eagles doing the same thing near Halibut Point Rec.