12 April 2016 – PNW Migration Update

Another night of moderate migration.  Seems like most movement was departures.

House Wren seems to be the new wave of summer residents to arrive en mass. But reports of early Western Tanagers and Swainson’s Thrush are popping up in the southern reaches of Oregon.

A new low pressure system is building offshore. If it holds off from forming rain cells we might get a nice southerly wind to push migrants northward tomorrow.


3 thoughts on “12 April 2016 – PNW Migration Update

  1. I live on San Juan Island. This time last year and the past years we have been swarmed with Rufous and Anna Hummingbirds. This year though we only have a couple. Very concerning. Is there any discussion anywhere about where they are or if something is different?


    • Jayne: I monitor most birding listservs during migration from San Diego to Portland. I haven’t heard any chatter about a drop in Hummingbird numbers. They are in the Portland area in usual numbers the best i can tell. Of course this is all anecdotal without any numerical analysis. I would be interested in seeing how this plays out in your location this year.


    • Jayne:
      I went into the eBird data base and pulled up the Frequency data for Rufous Hummingbird in San Jaun County and compared 2015 to 2016. Here is that data:

      2015 2016
      57 – – 34
      31 – – 29
      18 – – 23
      47 – – 18
      24 – – 59
      75 – – 68
      72 – – 21
      48 – 0.04 25
      39 0.03 0.05 21
      34 – 0.08 24
      57 0.12 0.13 39
      73 0.18 0.64 25
      52 0.23 0.78 18
      41 0.29 0.36 14

      The left two columns are data from 2015 the first column is Sample Size (number of checklists submitted) and the second is the “Frequency”: the percentage of checklists that report a species within a specified date range and region.

      The right two columns are 2016 data with Frequency first then Sample Size.

      Each row is one week starting Jan 1.

      From the data i see two things; first the sample size is down significantly in 2016, and two the “Frequency” of RUHU sightings is up significantly.

      (Unfortunately the formatting never comes out right on this platform so it may be a bit tough to read easily)



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