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Re: [CALBIRDS] "Cassiar" Dark-eyed Junco

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  • Kimball Garrett
    ... Before the advent of listserves, the standard approach was to go to one s bookshelf and pull down Grinnell and Miller s The Distribution of the Birds of
    Message 1 of 2 , Feb 25, 2004
      At 02:13 AM 2/25/2004 -0500, migratoriusfwlr@... wrote:

      > On February 19th I had a junco up here at the Arcata Marsh project that
      > fit the description of the "Cassiar" "subspecies" which breeds in the
      > northern Rocky Mountains in Canada. I was wondering if anybody could tell
      > me of the status of the "Cassiar" junco in California? And I would also
      > like to ask for the total number of records in California. I've never
      > heard any mention of this subspecies in any of the literature or on any
      > of the various california e-mail listserves.

      Before the advent of listserves, the standard approach was to go to one's
      bookshelf and pull down Grinnell and Miller's "The Distribution of the
      Birds of California." This is perhaps the most basic and important
      reference to the birds of the state and I can't imagine any birder being
      without it. The relevant section in G&M reads:
      Junco hyemalis cismontanus
      Cassiar Slate-colored Junco
      "Sparse but regular winter visitant from November to early
      April. More of the Slate-colored Juncos wintering in the State belong to
      this race than to J. h. hyemalis." Geographic range: "All sections of
      State except coastal islands and Colorado Desert" [and that limitation, no
      doubt, an artifact of coverage].

      In Alden Miller's (1941) "Speciation in the Avian Genus Junco" there is
      considerable detail about the appearance, distribution, and relationships
      of this subspecies. Miller notes that it winters "with fair regularity in

      >(I say "subspecies" due to much debate on the classification on this J.
      >hyemalis cismontanus as an actual subspecies due to this subspecies being
      >a well established product of Oregon and Slate-colored Junco hybridization
      >which apparently goes against the subspecies concept. )

      Miller again: "...it may be stated that cismontanus is a fairly uniform
      group of birds, doubtless of hybrid origin to begin with, which now
      perpetuates itself independently of further hybridization of the parental
      types J. oreganus and J. hyemalis. Cismontanus on the margins of its
      breeding range breeds freely with J. h. hyemalis, which it most
      resembles. In certain regions it does not interbreed freely with J.
      oreganus, whereas at other locations hybridization is evidently frequent."

      Since the breeding range of birds Miller classified as cismontanus is
      rather limited, it's likely that many "cismontanus"-like birds in
      California result from "Oregon" x "Slate-colored" hybridization occurring
      away from Miller's mapped range of cismontanus.

      A more detailed genetic/morphological study of juncos by George
      Barrowclough is ongoing, and it is perhaps an understatement to say that
      the results (many of which will be rather surprising) are eagerly anticipated.

      -- Kimball

      Kimball L. Garrett
      Ornithology Collections Manager
      Natural History Museum of Los Angeles County
      900 Exposition Blvd.
      Los Angeles, CA 90007 USA
      213-746-2999 FAX
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