>Dennis, I'd appreciate some speculation:
>
>What is your (or the other Tweeters') feeling for Anser X Branta goose
>crosses? I realize that they are both geese, but they certainly appear
>at least as different as Mergs and Bufflehead.
>
>I see several of these 'hybrids' ususally Domestic _Anser_ crossed with
>Great Basin Canadas (Branta canadensis moffitti) annually, including a
>Hybrid paired with a Canada this spring down south of Salem, OR.
>
>Would the F1 'Hybrid' produce viable offspring with the 'pure' Canada?
>
>Jon. Anderson

I don't know what's happening with hybrid geese around here, but from the
variety of those I see, including some that are just a little different
from the Canadas, I have a suspicion there are backcrosses.

Intergeneric hybrids in birds have typically caused people to look more
closely at their taxonomic relationships, for example in hummingbirds, in
which genera are often based on male characters that are probably easily
modified by sexual selection. A good discussion of this is in Sibley
(Condor 59: 166-191, 1957). I think hybrids in waterfowl, and in birds in
general, are more common within than between genera, but there have been
some between fairly distant genera, as (I think) Mallard x Muscovy Duck.
We have a hybrid in the Slater Museum one parent of which was surely a Wood
Duck, and I cannot figure out who the other parent was. My guess is that
the reason we don't detect female duck hybrids is just that they don't
stand out like the males do.

Cockrum (Wilson Bull. 64: 140-159, 1952) listed known North American
hybrids at that time.

By the way, I just looked up these references in a book I consider a
classic: The Birdwatcher's Companion, by Christopher Leahy, Hill & Wang,
1982. Get this book, memorize it, and you'll never run out of conversation
material at a birders' cocktail party.

Dennis Paulson, Director phone: (206) 756-3798
Slater Museum of Natural History fax: (206) 756-3352
University of Puget Sound e-mail: dpaulson at ups.edu
Tacoma, WA 98416