[Birdtalk] California Gull vs Ring Billed Gull

[Connie McManus]

I have been avoiding identifying gulls for the time being due to what I
think is a very complex group of birds!  Having said that, I can't turn away
from the excellent learning opportunity this conversation offers.  After
reading the original post about these two gulls, I went to the bird guid at
utahbirds.org, to Cornell's website, my trusty Sibley's and the USGS
Patuxent website.  It seems to me that the California Gull has a red spot on
the gonys and red around the mouth and eyes (in adults) where the
Ring-Billed Gull has a black ring around the gonys and surrounding the
eyes.  From the photos, both appear to have golden eyes.   In addition, I
have also noticed the California gull seems darker and the Ring Biiled seems
to be whiter from a distance.  So, am I off on a wild one, or are the red
and black colorations valid identifiers between these two gulls?


-- 
Connie McManus
Nibley, Cache County, Utah


=====================

On Sat, Apr 5, 2008 at 10:07 PM, Cliff and Lisa Weisse <
CliffandLisa at octobersetters.com> wrote:

> I'll take a stab at this.  First, consider the possibility that both
> Ring-billed and California Gulls roost at that location.  That said there
> are definite differences between these species, even in flight at a
> distance.
> Adult California has a darker mantle, so it appears to contrast less with
> the black wing tips.  Mantle shade can look quite variable depending on
> angle of sun so be cautious when using this mark.  Ring-billed also has
> lighter gray between the black wing tips and the gray of the mantle and
> inner wings.  This bright flash is visible at considerable range.
>
> Adult California tends to have more extensive black on the wing tips but
> both species vary a lot.  California also tends to have larger white spots
> on the outer primaries.
> Shape can also be useful.  To me Californias are fairly easy to recognize
> by the longer, proportionately narrower wings and slender body.
>  Ring-billeds look stubbier bodied and shorter winged in flight.  These
> structural traits can be seen from a long way off.  Shape has the advantage
> that it can be used for all ages.
> Another thing that really helps me is the bill on California Gull.  It's
> long and thin with square cut tip and almost no visible bulge at the gonys.
>   No other North American large gull has a bill shape like this.  They're
> either shorter and thin or bulkier/thicker and often have pronounced bulge
> at the gonys.  With practice you can recognize that shape easily even if you
> can't see the color well.
> Hope this is helpful.
>
> Cliff
>
>
>
>
> birdnet at skylace.net wrote:
>
> > Is there any reliable way to distinguish
> > California Gulls from Ring Billed Gulls
> > at a distance?
> >
> > The reason I ask, is that during the winter
> > I sat on the flyway where gulls were coming
> > in to spend the night on a lake. About 200
> > gulls came close enough for me to see the
> > eyes. Every gull who's eyes I could see had yellow eyes (ring-billed).
> > The next day one of my favorite posters to
> > this group said that s/he had observed a flock
> > of California gulls at the lake.
> >
> > So I went back to the lake and observed another
> > hundred gulls at close distance, and every
> > one of them had yellow eyes (ring-billed).
> >
> > I think the other poster was wrong about the
> > identification even though s/he is very knowledgeable about the birds of
> > Utah.
> >
> > Beyond about 100 feet I am clueless about whether
> > a gull is a California Gull or a Ring-Billed Gull,
> > and if even an expert goofs I wonder if eBird might
> > benefit from a California/Ring-Billed category?
> >
> >
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> > Birdtalk at utahbirds.org
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> >
> >
> >
> >
> >
>
> --
> Cliff and Lisa Weisse
> Island Park, Idaho
> cliffandlisa at octobersetters.com
>
>
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