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Subject:

Correction: Black-headed Gull (not Bonaparte's) at Schoolhouse Pond

From:

Fred Shaffer

Reply-To:

Fred Shaffer

Date:

Fri, 5 Feb 2010 23:28:11 -0500

After going over my digiscoped photos and getting feedback from a variety of knowledgeable gull watchers, I am correcting my earlier identification of the small hooded gull seen earlier today at Schoolhouse Pond.  My marginal photos and my observations from the field support an identification of Black-headed Gull.  Initially I identified it as a Bonaparte's Gull.  But several features gave me pause and caused me to take the second look at it after work today and then to e-mail out a few of my photos for comments.  

I passed it off as a Bonaparte's because it had a relatively washed out, blackish gray bill (with only a slight reddish tinge).  The bird did not have the bright reddish-orange bill that I am used to seeing on adult BHGU.  The bill wasn't jet black, but a more diffuse dark gray with a faint reddish tinge (visible when I zoomed in and in some of the photos).  Also the bill was slightly thicker and longer than I was comfortable with for a Bonaparte's Gull.  The apparent shade of the bill may have been affected by the overcast and snowy conditions as well.

However, it was the size that really caused me to question my identification.  The gull appeared relatively large in comparison to the surrounding gulls, being only only slightly smaller than the nearby Ring-billed Gulls, not significantly smaller as a Bonaparte's would have been.  The bill shape and size and the overall size of the bird was observed and photographed from a variety of angles and not impacted by the snowy conditions and poor light like the shade of the bill was.

Thank you again to those who provided feedback and insights on this bird.  And, I hope my mistake didn't keep others from seeing the gull.  By the time I left (around 3:30 or so) the snow was getting pretty heavy, visibility was getting worse, and the gulls had flushed for some reason.  Most of the gulls left and I lost track of the BHGU.  This is the third Black-headed Gull that I've seen at Schoolhouse Pond.  The others were on December 16, 2004 (found by Hans Holbrook) and December 17, 2007.  And I believe that Rob Hilton had a BHGU at the pond early in 2009 as well.   At least with ones I've seen at the pond, the BHGU was loosely associated with the surrounding Ring-billed Gulls.  Perhaps this bird will hang around for awhile like the 1st winter Iceland Gull did in January.

Fred Shaffer
Crofton, MD