Hi Tweets,

Jerry Tangren writes (edited):

>...what is a stable population of apparent
>hybrids? That statement makes no sense!

Well, perhaps it does in certain instances: Western Gull Larus occidentalis
and Glaucous-winged Gull L. glaucescens, for example. I used to like the
idea--purely intuitively, of course--that they were two morphs of one
species. I've been chewing on the idea it's maybe more complicated than that.

>Please emphasize that this is a
>population of birds intermediate along a continuum between eastern birds
>and western birds.

Should you pass this suggestion along to Jim Rising, or should I?

>They aren't hybrids. I'm not even sure they are
>intergrades?

Umm, perhaps. I did a breeding bird survey in the 'cismontanus'
north-central part of BC a few years ago, and I can say with certainty that
in most breeding pairs there was an almost full range of characteristics
between 'oreganus' and 'hyemalis', and that either pure-plumage hyemalis or
oreganus were impossible to find without making elastic the definition of
what constituted either. Hopeless...

>And then perhaps only because the gene combinations produce birds that
>are readily separable from others with slightly different combinations.

To which we give provisional vernacular names. I wish the various naming
bodies would make clear that, as the history of nomenclature demonstrates,
these vernacular names (and in some cases taxonomic names also) are clearly
not written in stone but--until definitive genetic relationships are
established--more often than not constitute a temporary 'best-guess' as to
who is related to whom.

>We're not really sure what are 'oreganus' genes vs. 'cismontanus' genes
>vs. 'hyemalis' genes. They are called Slate-colored Juncos because back
>when the species boundaries were being drawn is was decided to put
>cismontanus in that group. And on that basis it is still proper
>to call them Slate-colored or better yet Cassiar Juncos, if you want a
>common name, but not hybrids!

I like the idea of a Cassiar Junco, but there may be a clinal difference
only. Until someone can nail those little DNA molecules down, it's going to
be a guessing-game.

Michael Price A brave world, Sir,
Vancouver BC Canada full of religion, knavery and change;
mprice at mindlink.net we shall shortly see better days.
Aphra Behn (1640-1689)