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RE: [CALBIRDS] Pine Grosbeak subspecies

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  • Kimball Garrett
    Jim (and CalBirders), I agree with Les Chibana that we re not likely to pin down the subspecies of the Kern County Pine Grosbeak, but here are a couple of
    Message 1 of 5 , Nov 9, 2004
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      Jim (and CalBirders),



      I agree with Les Chibana that we're not likely to pin down the
      subspecies of the Kern County Pine Grosbeak, but here are a couple of
      additional thoughts (some of which were developed with Jon Dunn as we
      watched the bird on 6 November).



      Bill size and shape does vary geographically (see BNA account #456 by
      Adkisson, 1999), but mean size varies (within a sex) only by 1.1 mm in
      culmen length and 1.7 mm in bill depth. I agree that this bird looked
      rather thick-billed, and the resident Sierra Nevada subspecies (Pinicola
      enucleator californica) has the most slender bill [bill length/depth =
      1.24; in other ssp. this ratio varies from 1.02 to 1.16]. This would
      perhaps argue against the Kern bird's being californica, but of course
      we have no measurements of the bill, just impressions from field and
      photos.



      Although californica breeds within 150 km or so to the north of Galileo
      Hill, it is not necessarily the only candidate for vagrancy; in fact,
      given the dearth of known records of this ssp. in the lowlands, I wonder
      if it isn't a poorer candidate than boreal leucura (including
      "alascensis" and "eschatosa") which is well-known to move into the
      northern couple of tiers of states during exceptional winters, or Rocky
      Mountain montana (with at least some down-mountain movement recorded).
      It doesn't seem likely that Alaska/B.C. coastal flammula would move well
      southward, but I'm not sure anything about the Galileo bird would rule
      that subspecies out [the AOU 1957 checklist says flammula has been
      recorded in winter south to n. WA and nw. ID, but Adkisson's BNA account
      says that winter British Columbia specimens are leucura and montana and
      that flammula only wanders to the n. BC coast]. I don't know the details
      of the Siskiyou/Lassen records cited in various sources or the Modoc
      record noted by John Sterling, but wonder if and how racial identity was
      determined.



      Plumage varies geographically as well, but we're hampered by not even
      knowing the sex of the Kern bird. My impression was that the primary
      coverts were rather slaty and cleanly edged with white, which might
      argue for an AHY bird (and therefore certainly a female), but can
      somebody with more familiarity with cardueline finches check the photos
      and see if they agree? If a HY bird, then the bird can't be sexed. Not
      knowing the age and sex for certain, it's difficult to apply any plumage
      subtleties to the question of subspecies. The back showed some
      indistinct dark centers, a character that varies a bit geographically,
      but without having the bird in the hand and knowing age/sex, it's of
      questionable value.



      I think we can rule out the endemic Queen Charlotte ssp. carlottae by
      plumage (that one is dark), and ne. Asian kamtschatkensis (vagrant to w.
      Alaska) by range, but maybe that's as far as we can get for certain.



      Far and away the best characters for determining geographical origin are
      vocal ones. Adkisson has studied this in detail (see Condor 83:277-288,
      1981). The loud whistled "location calls" (including "flight calls")
      show striking geographic variation; to my knowledge, nobody heard such
      calls from the Galileo bird. The Galileo bird did give quiet, repeated
      "contact calls", but according to Adkisson there is no geographical
      variation in such calls.



      So in summary I can emphatically say that I don't know the subspecies
      (and, thus, the rough geographical origin) of the Kern bird, and now
      that the bird is apparently gone we're not likely to ever know. If the
      bird got munched by an Accipiter, perhaps someone will find a pile of
      feathers that can be used for genetic analysis???



      -- Kimball





      Kimball L. Garrett

      Ornithology Collections Manager

      Natural History Museum of Los Angeles County

      900 Exposition Blvd.

      Los Angeles CA 90007

      (213) 763-3368

      (213) 746-2999 FAX

      kgarrett@...





      -----Original Message-----
      From: vireos44 [mailto:jpike44@...]
      Sent: Thursday, November 04, 2004 10:27 AM
      To: CALBIRDS@yahoogroups.com
      Subject: [CALBIRDS] Pine Grosbeak subspecies



      Hi all, Having looked at the Pine Grosbeak photo taken at Galileo

      Hill on Joe Morlan's site, I'm impressed with the length and depth

      of this bird's bill. That is one big bill! Having gone through pics

      in various books (Small;Kaufman;Audubon Society Master Guide) and

      followed that with an internet search, I haven't been able to find a

      picture of a PIGR bill that equals its size. According to Pyle,

      among the six PIGR subspecies occurring in North America, the

      California breeder (californicus)has the smallest bill. The two

      subspecies with the largest bills are a Siberian vagrant

      (kamtschatkensis), and an Alaskan-British Columbia breeder

      (flammula) that winters to Washington-Idaho. I wouldn't hazard a

      guess as to which subspecies this bird is, but I question whether it

      could be the California one.



      Jim Pike

      Huntington Beach



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