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Frigatebird sp., Arcata, Humboldt Co. 15 July 2007

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  • Brian Sullivan
    Hello all, Yesterday evening (15 July 2007; ~18:30-19:15) we (Brian L. Sullivan, C.J. Ralph, Peter Ralph, Marshall J. Iliff) were fortunate enough to have a
    Message 1 of 1 , Jul 16, 2007
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      Hello all,



      Yesterday evening (15 July 2007; ~18:30-19:15) we (Brian L.
      Sullivan, C.J. Ralph, Peter Ralph, Marshall J. Iliff) were fortunate enough
      to have a female-plumaged frigatebird fly past us (first spotted by PR)
      while seawatching from Lamphere Dunes, west of Arcata, Humboldt County,
      California. It flew north away from us and the circled around, and,
      amazingly, perched in a Shore Pine in the dunes. Steven T. Kelling was
      nearby and was able to join us in observing the bird, but unfortunately a
      large number of northern California chasers arrived minutes too late. During
      its 20+ minutes in the tree we had close (100m) studies of the birds in
      scopes and were able to get decent photos of it perched (MJI) and excellent
      ones in flight (BLS). Although mid-July is at the beginning of what has been
      considered a "Magnificent Frigatebird" vagrancy window in California, we
      have been cautious about labeling this bird based on assumptions.

      Brian has uploaded photos to his Flickr site:
      www.flickr.com/photos/oceanites

      A description is posted below based on our field observations and the
      photos.



      We are interested in opinions on this bird. We believe Great
      Frigatebird is eliminated by the partial collar that wraps into the throat
      feathering, thus suggesting a subadult female that will acquire a fully
      black head. Although our size impressions in the field did not suggest
      Lesser (which none of us has seen), we believe that several plumage
      characters may favor that species over the more probable Magnificent. Among
      those are:



      1) Cinnamon feathering on the lower throat just below the partial black
      collar; as we understand it, cinnamon feathering in immature frigatebirds is
      expected in Great and Lesser, but not in Magnificent



      2) White axillaries that appear too extensive for Magnificent, which
      typically has narrow white scalloping



      3) Pinkish orbital ring at a fairly mature stage; adult female Magnificents
      would have a gray or bluish orbital (red in female Great)



      4) Pinkish or horn-pink bill; Magnificent typically (always?) has a grayish
      bill



      We are not sure if the lower breast pattern or fairly bright greater covert
      bar are useful in the Magnificent vs. Lesser question. As a review, Lesser
      Frigatebird is known from three US records: ad. male 3 Jul 1960, Deer Isle,
      Maine; ad male Wayne Co., MI, 11 Sep 2005 (see Brennan and Shultz 2006, NAB
      60:164-65); and a recently discovered record (date?) from Wyoming; there are
      also Hawaii records. This would thus be mainland North America's fourth
      Lesser and the first for the West Coast. Great Frigatebird is known from two
      photographed CA records (Mar and Oct) and one Oklahoma record (3 Nov 1975).



      A description of the bird, compiled from memory and from photos, is below my
      signature block.



      Best,



      Marshall Iliff & Brian Sullivan

      eBird coordinators

      Miliff AT aol.com & Heraldpetrel AT gmail.com

      West Roxbury, MA & Monterey, CA



      **********************************************************************

      DESCRIPTION



      SIZE AND SHAPE: In the field we felt it was consistent in size and structure
      with Magnificent Frigatebirds we have seen elsewhere.



      HEAD PLUMAGE: It was largely white-headed, but had significant black on the
      nape that wrapped around the lower face to form a partial collar, recalling
      the head pattern of a *Pterodroma* petrel such as a Hawaiian Petrel. The
      collar seemed to almost connect in the front under the throat, but photos
      clearly show a break in the central portion of this collar. The head was
      largely white with a few black flecks in the crown (see photos), a
      white-collared effect behind the black nape, and a few whitish chevrons in
      the upper back. Just below the collar was a small but distant patch of
      cinnamon-buff feathering that was located centrally on the lower
      throat/upper breast.



      BODY PLUMAGE: Belly, undertail coverts, and tail were black, as were the
      flight feathers. A prominent pale greater covert bar was present and visible
      on the upperwing. BLS noted that it was whiter towards the leading edge and
      more buffy or tawny towards the rear. A white patch was restricted to the
      chest and at its lower margin was rounded at the edge and concave at its
      lower margin, with a small finger of black extending a short distance up the
      central breast. There were distinct patches of white in the axillars, which
      appeared to involve at least two adjacent rows of completely white axillar
      feathers.



      SOFT PARTS: The bill was quite slender and horn-pink in color. The orbital
      ring was apparent in the field and was pinkish-flesh, seeming most prominent
      in front of the eye. The feet were small and pinkish-flesh, close in color
      to the orbital ring.






      --
      Brian L. Sullivan
      eBird Project Leader
      <www.ebird.org>
      Photographic Editor,
      Birds of North America Online
      <http://bna.birds.cornell.edu/BNA/>
      Cornell Lab of Ornithology
      159 Sapsucker Woods Rd.
      Ithaca, NY 14850

      Photographic Editor,
      North American Birds
      American Birding Association
      <www.americanbirding.org>

      bls42@...
      609-694-3280
      -------------------------------


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