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. <http://www.mbr-pwrc.usgs.gov/infocenter/i0600id.html>
Another good site, especially about molts, with photos, is "Anything Larus" by Amar
Ayyash at <http://www.anythinglarus.com/2010/11/preformative-molt-and-bonapartes-gull.html>
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. <http://depts.washington.edu/coasst/>
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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