On Thu, 16 Jan 1997, Denny Granstrand wrote:

> A name like Olympic Gull is certainly easier that Western Gull x
> Glaucous-winged Gull hybrid. When a hybrid becomes this common it should be
> named.

Question from a naive gull-watcher:
(also relating to Patrick Scott's question: "with hybrids ... how
does one find out for sure what species the bird is?")

I am curious to know what the evidence is that the "Olympic Gull" is
really a hybrid of western and glaucus-winged. And if these two parental
"species" really interbreed so successfully and commonly, why aren't all
three forms considered to be subspecies of the same species? When these
are called "hybrids", I presume this isn't taken to imply that each of
these birds has one western parent and one glaucus-winged parent (or is it?)
I am imagining that the case is more similar to the red wolf, which
recent DNA evidence suggests may be a "hybrid" of the gray wolf and
coyote. (Not everyone accepts this interpretation.)

Can anyone clarify why these birds are thought to be hybrids and to what
extent they interbreed with each other and with westerns and glaucus-wingeds?

I can think of potential methods to try to measure the relatedness of
these three gulls using DNA fingerprinting techniques, but have these
actually been done? One would probably need to test a lot of individuals
to get a clear picture. Did the Sibley/Ahlquist reannealing tests address
relatedness at a level this specific?

Paul Talbert
paul at sparky.fhcrc.org