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Re: [CALBIRDS] Dan Murphy's Allen Hummingbird Sighting in N. CA: Today......

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  • dsuddjian@aol.com
    In a message dated 1/31/2010 9:23:51 AM Pacific Standard Time, edelstein@earthlink.net writes: Did other folks in central and n. CA see Allen s returning
    Message 1 of 3 , Jan 31, 2010
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      In a message dated 1/31/2010 9:23:51 AM Pacific Standard Time,
      edelstein@... writes:

      Did other folks in central and n. CA see Allen's returning recently, too?
      At Santa Cruz County the average arrival date for the 1st reported migrant
      Allen's Hummingbird during the 40-year period 1969-2008 was Jan 15 (standard
      error +/- 10 days), and for the more recent 10-year period of 1999-2008 the
      average arrival was Jan 10 (+/- 7 days). 1st arrivals have shown a highly
      significant trend for earlier dates over 40 year period. I believe this
      year's 1st arrival for SCZ was Jan 11. You can see a plot of the arrival dates
      for SCZ for Allen's and a number of other spring migrants here:

      _http://santacruzbirdclub.org/Spring%20Arrivals-08.pdf_
      (http://santacruzbirdclub.org/Spring%20Arrivals-08.pdf)

      A number of species have exhibited notable changes in the timing of
      arrivals over recent decades, most especially for species that arrive in late
      winter or early spring. The info cited in the Marin County breeding bird atlas
      may not well reflect the more recent situation for some species of migrants.

      David Suddjian
      Capitola


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