Jack Bowling wrote:

>Al had pondered and decided that it would be unlikely that White-throated
>and Golden-crowned Sparrows would hybridize because of the ecologically
>separated breeding grounds. I concur with this judgement: White-throats
>are lowland early-to -mid succesional habitat specialists while
>Golden-crowns are almost exclusively sub-alpine Krumholtz/scrub willow
>zone specialists, at least in B.C. Even in Fort Nelson in northeast B.C.
>there is still a healthy altitudinal separation between the two species,
>although around Liard Hotsprings on the Alaska Highway it is likely not
>much more than 300 metres. Perhaps in the southwestern Northwest
>Territories or southeastern Yukon where the sub-alpine descends to lower
>elevations it would be more of a possibility.

In a way, hybridization may be *more* likely in cases in which species
scarcely overlap. An individual of species A at the edge of its range may
be unable to find a mate, while there may be many available unmated
individuals of species B in the same area. This may account for the
majority of wild hybrids.

The songs of the two sparrows, although not identical, certainly have some
features in common. Their high, pure, sweet whistles evoke the same
feelings in me.

Sometimes one does a doubletake on a subject line. For a second, I thought
I was reading "weird Al's sparrow." ;-)

Dennis Paulson 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