Subject: Re: species concepts
Date: Jun 22 15:06:34 1995
From: Jon Anderson - anderjda at dfw.wa.gov


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
Olympia, WA
anderjda at dfw.wa.gov


On Thu, 22 Jun 1995, Dennis Paulson wrote:

> I have never heard of this hybrid combination before, but I have seen both
> a specimen and a wild bird that I thought were hybrid Black-capped X
> Mountain chickadees. Isolated hybrids of this sort have absolutely no
> relevance to the species concept, but it is always of interest to see what
> species will hybridize, especially in nature; it probably gives us some
> indication of relatedness (don't read this, David). For example,
> goldeneyes and mergansers have hybridized frequently, which seems bizarrre,
> yet in fact they're not distantly related, something that wasn't realized
> when the first hybrids were reported. And juncos hybridize with some
> sparrows, again a little surprising until you realize that they are in fact
> closely related.

Of course, Mallards will cross with most of the dabbling ducks they can
'encounter'. I have banded 1 and seen several other Mallard X Pintail,
and my father, while duck hunting, shot (and ate - couldn't afford to
mount it) an Am Wigeon X Pintail drake. !!It dawns on me that I've never
seen a *female* hybrid duck.

> Many hybrids have been produced in captivity, even between birds that don't
> seem especially closely related. This is probably because if you put a
> male of species X and a female of species Y in a cage, lacking appropriate
> mates but possessing an urge to breed, they may eventually get it on.

"Dats and Cogs"?

> About hybrids--the burden of proof is on the hybrid proponent, as sometimes
> an easier explanation is that a bird is an aberrant individual of its
> species. If I recall correctly, the Black-capped X Chestnut-backed was
> never photographed or captured and measured, which is a shame.