Subject: Re: White-crowned Sparrow puzzler
Date: Jun 7 20:11:22 1996
From: steppie at wolfenet.com - steppie at wolfenet.com


>Hi Tweeters, here's a puzzle I hope you can help solve. I'd appreciate
>any help available. First, the background:
>
>Three distinct subspecies of White-crowned Sparrow are known to breed in
>Washington. Z.l. pugetensis, the widespread bird of western Washington,
>Z.l. gambelii of subalpine/alpine habitats in western Okanogan Co., and
>apparently locally south to Naches Pass (did I get that right Gene?), and
>Z.l. oriantha which is known to breed at Mt. Salmo in Pend Oreille County.
>No Breeding Bird Atlas data indicate that White-crowned Sparrows breed in
>the Blue Mts. Larrison (in Weber and Larrison 1977) stated that Z.l.
>oriantha breed in the Blue Mts. Subsequent conversations with folks
>(especially Russell Rogers) indicate that there is very little evidence
>available to support that claim. Dennis Paulson has noted that he heard
>singing birds up there once, which is the only real evidence that I had
>been able to uncover.
>
>Until today that is, when I got the following data from the Conner museum
>on two specimens taken in late June 1977. The museum label data is listed
>here:
>
>#77-548 .3 mi E, .1 mi N of Mt. Misery, 6200', Garfield Co., WA
> 25 June 1977 D.P. Mack 143 (Coll. R.E. Johnson)
>M, testes L11x8, R12x8, no bursa, sl. fat, no molt, skull os., 25.6 g.
>
>#77-630 .3 mi E, .1 mi N of Mt. Misery, 6200', Garfield Co., WA
> 25 June 1977 D.P. Mack 163 (Coll. R.E. Johnson)
>M, testes L11x7, R12x7, no bursa, sl. fat, no molt, iris brown, skull os.,
>25.4 g.
>
>
>So the puzzle is this. With the information given above, is it possible
>to tell whether or not those birds were in breeding condtion at the time
>they were collected. I assume the tell-tale measurement would be testes
>size, but I know very little about this. Is that size indicative of
>breeding? Are there confounding factors which don't make the solution
>that easy? I didn't get subspecies from the museum, but have put in a
>request for that info if they have it.
>
>There is also the likelihood (Dennis mentioned this) that White-Crowned
>Sparrows breed irruptively in the Blue Mts. in response to climatic and
>habitat changes throughout their range. So it could be that in the late
>70's Larrison wasn't going out on a limb, but now the sparrows are not to
>be found in that region.
>
>A thorough discussion amongst tweeters about this would make me very
>pleased, and might hash out some answers. At the very least, this data
>gives me somewhere else to check when I head out there next week.
>
>

My only comment to the above discussion is that pugetensis might be the form
at Naches Pass, as there has been a distinct movement up to and over the
Cascade crest at Snoqualmie Pass most likely in response to logging. The
same situation appears to be the case at Potato Hill north of Mt. Adams and
about Glenwood in Klickitat County. If this is the case, then understanding
the breeding dist. of the various forms in WA seems clearer (at least to me).
Andy Stepniewski