[rba] [mou] Laughing Gull in Olmsted County

[rba at moumn.org]

Since no one else has commented on the ID of this possible Laughing  
Gull as of Sunday morning, here are some thoughts which I hope are of  
some help. First of all, this is under-appreciated ID problem not  
fully covered in the standard field guides, since first-summer (i.e.,  
one-year-old) Franklin's Gulls can closely resemble adult and near- 
adult plumaged Laughing Gulls. This is because the upper wing surface  
of these Franklin's Gulls can lack the white bar separating the black  
outer primaries from the dark gray on the rest of the upper wing  
surface. This upper wing pattern in flight, therefore, can look like  
the pattern of an adult Laughing Gull.

For these problematic birds, I think the best way to separate them is  
to look at the UNDER side of the wing in flight. Here, the black on  
the Franklin's is limited mostly to the distal half of the outer  
primaries; on an adult and near-adult Laughing the black is more  
extensive, including the full length of the outer primaries and  
usually extending partly into the primary coverts and the inner  
primaries. Was the under wing pattern visible to any of the observers?

Looking only at Paul's two photos, I'm reluctant to comment  
confidentally on its ID, since they do not show either the upper or  
under surface of the spread wing. But the photos do show an incomplete  
hood (if a Franklin's, this is consistent with it being first-summer),  
thick eye-crescents (suggesting a Franklin's), and the hard-to-see  
bill seems to be thin and short (again suggesting Franklin's). If  
there were direct comparison with other gulls, perhaps the ID would  
become clearer, since the Laughing Gull is larger overall with more of  
a longer- and pointed-winged profile.

Hopefully, other observers took field notes of this Rochester gull  
(and the one reported in Wabasha County a few days ago) so the ID  
becomes clearer. And, if either gull turns out to be a Franklin's, the  
observers should certainly not feel badly, since many other birders  
have long struggled with this problem. Several years ago in Minnesota,  
there had been several reports of Laughing Gulls, some by experienced  
observers (myself included!), some of which the documentations were  
later reexamined to show they were more likely Frankin's Gulls.

Again, this ID problem has never been fully covered in any of the  
field guides, and the only reference I know of which discusses it is  
Kenn Kaufman's 1990 book A Field Guide to Advanced Birding: see pages  
112-113.

Kim Eckert


On Jun 14, 2008, at 9:07 PM, Paul Pedersen wrote:

> Several of us who saw the possible Laughing Gull this morning in  
> Olmsted County would like some feedback from the listserve based on  
> photos I took of the bird.  The photos are not the greatest quality  
> but they are the best we have.  We thought we would open it up for  
> some discussion and opinion from others who might have more  
> background in plumage, age and molt of this gull. Check this link on  
> the MOU website and reply to the group.
>
> http://moumn.org/cgi-bin/recent.pl?op=showcase
>
> By the way, we watched the gull for about 20-30 minutes before it  
> took off about 10 AM and flew towards the southwest and out of sight.
>
> Paul Pedersen
> Rochester, MN
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