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Arctic Tern photos

From:

David Czaplak

Reply-To:

David Czaplak

Date:

Wed, 30 Jun 2010 14:04:36 -0700

The Arctic Tern was not to be seen anywhere at 6AM. It popped up after 9, from who knows where. It flew 3 miles upriver to beyond Ten-foot Island, came back down, and mostly remained settled on the rocks. I was able to see it much better with the Questar at 80x. The bill is short and red, the legs also shorter than those of Common. The tail streamers in most poses are even or just a bit longer than the wingtips. The gray underparts are mottled and patchy, but there is gray across the cheeks in some lights, almost to the cap. One of yesterday's photos showed just the barest hint of a dusky bar along the dorsal leading edge of the inner wing. I think these features suggest "second summer" type plumage. I imagine that not-quite-adult waterbirds are more likely to drop in at such an inland location. (I am thinking of the sub-adult Pomarine Jaeger that Paul O'Brien found here on 10JUL 1990.) All of the primaries are very translucent in the right backlighting, contrasting with the fine black primary tips on the underside.

The flight style was usually more bouncy that that of Common Tern, but occasionally languid. I saw it catch many fish. I watched it perform the hover-step dive described in some books: The bird stops it's forward motion, and with body angled down at 45 degrees, drops halfway to the river. Next it stops, pulls the body up 30 degrees above the horizontal, and hovers. Finally, the wings stop beating, and it looks like it is going to belly-flop into the water. At the last minute it noses over and plunges in head first. A few time it also did a standard plunge dive.

I was able to get a bit closer to it by wading into the river below the lock, almost out to the second row of islets. New photos at:


http://www.flickr.com/photos/39566052@N06/sets/72157624393128436/detail/

Dave Czaplak