Subject: Re: Slate-colored Juncos
Date: Feb 13 11:55:18 1995
From: Dennis Paulson - dpaulson at ups.edu


Dave Nunnallee wrote:

>Have there been any studies, or scientific guestimates, of the frequency of
>Slate-colored occurrences here in Washington? I believe some time in the
>past I heard someone speculate that maybe one junco in 200-300 is a
>Slate-colored; does that ring true?

I think that's not too far off the truth, although there is probably
tremendous local variation. I think Slate-colored are more common east of
the Cascades, but that's very subjective. Maybe Russell Rogers or Gene
Hunn have better data.

>The individual visiting my feeder has a trace of brown on the back; I
>presume that reflects some hybridization with our Oregon race juncos?

Probably most of our "Slate-colored" juncos here are Junco hyemalis
cismontanus, which breeds in southern AK, southern YT, and northern BC.
It's distinctive characteristic is the brownish suffusion on the back. We
do have Junco h. hyemalis from farther north in Alaska too, in smaller
numbers (no brown on back).
>
>One interesting thought that occurred to me, as I recounted the ten or so
>Slate-coloreds I have seen here in Washington, was that I have never
>identified a female of this race. I presume that is a testimony to my poor
>observation skills, and to the similarity of these females to pale female
>Oregon Juncos - but have others noted female Slate-coloreds here?

Yes, I've seen females. Any sex or age should be easily distinguishable
because the gray hood color continues on the sides, whereas in Oregons the
hood and side color are dramatically different. This is much the best way
to distinguish the two types, I think. This winter I have a bird in my
yard that I'm pretty sure is an intergrade between cismontanus and Oregon,
with a much richer brown back than typical cismontanus and with just a hint
of reddish on the sides, which are mostly gray. Birds like this (from
where the breeding ranges approach) are what prompted the decision to lump
the two types.

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