[Birdtalk] California Gull vs Ring Billed Gull

[Cliff and Lisa Weisse]

Jim,

Head streaking of varying extent is seen on gulls during winter but 
adults have clean white heads during summer.  There are exceptions like 
Western Gull which has no streaking or a very small amount.  Some 
Glaucous Gulls have little or no streaking as well but most species 
develop streaking.  Other changes include duller bare parts color during 
winter (legs, bill, eye ring) and sometimes some black or blackish on 
the bill.  They molt all their feathers in summer so the feathers are in 
their most worn condition now.  If you look at the bottom two photos on 
your page the California Gull with wings raised has visible wear on the 
primaries most easily seen on P5-7 (counting back from the outermost 
feather on the wing these are the 4-6 feathers in from the end of the 
wing and they have more pointed, notched tips where the feather has worn 
away from beside the shaft.  Gulls molt some of their body feathers in 
late winter/early spring in preparation for breeding and that's when 
they lost the head streaking. 

Cliff

Lofthouse wrote:
> Good stuff Cliff.  Thanks.
>  
> Would you care to comment on the lack of streaking on the nape of the 
> gulls in my pictures?
>  
> Sibley shows that to be pretty obvious on the CAGU. 
>  
> Jim
>  
> PS  I have sent several posts on this subject and none of them have 
> made it back to my inbox.  They must be going though as you have 
> answered.  I wonder where the bottle neck is?
>
>     ----- Original Message -----
>     *From:* Cliff and Lisa Weisse
>     <mailto:CliffandLisa at octobersetters.com>
>     *To:* Lofthouse <mailto:jbloft at wildblue.net>
>     *Sent:* Monday, April 07, 2008 8:57 PM
>     *Subject:* Re: [Birdtalk] California Gull vs Ring Billed Gull
>
>     Jim,
>
>     The CAGU in the photo you link below has more obvious gonys and
>     less blunt tipped bill than most CAGUs.  The bill typically looks,
>     especially at a distance, like you cut the eraser end off a pencil
>     and stuck it on the gulls head.  Obviously I'm not saying the bill
>     is that square but that's the general impression, especially
>     compared to other large gulls.  For an example of a more pointed
>     bill look at this Mew Gull:
>     http://www.camacdonald.com/birding/DesJardin/MewGull2.jpg
>
>     And for a bulbous tipped bill (definitely not parallel edged-the
>     line of the bottom of the bill is on a distinctly different plane
>     than that of the top) see this Western Gull:
>     http://nationalzoo.si.edu/ConservationAndScience/MigratoryBirds/Featured_photo/Images/Bigpic/wegu1.jpg
>
>     I'm not talking about big differences but there are definite
>     average differences that often give species a distinctive
>     appearance.  On the surface the Western Gull looks very similar to
>     the California Gulls in your photos, dark back, yellow bill, dark
>     iris, black wings with white spots on the ends of the primaries. 
>     Obviously it doesn't have yellow legs or black on the bill (but
>     remember that CAGUs will often lose the black) but it would jump
>     right out at you if you saw this bird at Walmart tomorrow.  Look
>     at your gulls again, really look them over, then flip to this
>     image.  It just looks different.  That's because of subtle
>     (although a lot less subtle in this case) differences like the
>     heavy bulbous-tipped bill, bulky body, and small beady eye.
>
>     Again I hope all this is useful. 
>
>     Good birding.
>
>     Cliff
>
>      
>
> ------------------------------------------------------------------------
>
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-- 
Cliff and Lisa Weisse
Island Park, Idaho
cliffandlisa at octobersetters.com

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