Sunday, August 4, 2013 juvenile Bonaparte's Gull discovered

Seward Alaska Sporadic Bird Report

Robin C dropped off a dead bird this afternoon that he found on the beach. Neither of us recognized the small, tern-sized bird with a black band on its straight tail. The small, straight bill was not that of a tubenose either. Must be a small gull. I ran it through the dead bird flow chart in my "Beached Birds, A COASST Field Guide to Alaska" by Dr. Julia Parrish.

Unlike a traditional field guide, this book starts out with questions about the feet. Webbed, free, or lobed? Webbed. Webbing complete? Yes, How many toes? Four. Fourth toe thin? Yes. Heel swollen? Yes. That took me to the Gulls, the Larids, and on to wing coloration, which was black-tipped primaries and gray secondaries. That led to the Bonaparte's and the metric measurements for bill, wing chord, and tarsus were right in the ballpark.

I also Googled for more information and found the USGS website to be very helpful. <> Another good site, especially about molts, with photos, is  "Anything Larus" by Amar Ayyash at <>

The specs all came out to a BONAPARTE'S GULL, juvenile. This is very interesting as we usually don't see them in the Seward area. I have records of a few adults in December 2007, July 2010, July 2011, and June 2012, though this may not be complete.

Perhaps the recent big storm caught this juvenile during its migration and the surf deposited it up on the beach. All along the Pacific coast, volunteer seabird survey teams participate in the COASST program, documenting dead birds like this young Bonaparte's, and the health of their beach on a regular schedule. This valuable citizen science database helps establish a baseline useful in assessing any impacts, and thus help to manage and protect the nearshore ecosystem.

There's a lot more information on the COASST website. <>
Maybe you would like to join and help monitor a beach near you!

Happy Birding!
Carol Griswold
Seward Sporadic Bird Report Reporter

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