Subject: [Tweeters] Migration and the back fill theory
Date: Mar 8 10:42:47 2008
From: mike denny - m.denny at charter.net


Hello All,

Migration is well underway here in southeastern Washington with Long-billed
Curlews, Am. Avocets, Caspian Terns, White-throated Swifts, Says Phoebes,
Savannah Sparrows, Vesper Sparrows and some swallows arriving here this
coming week. Over the last 25 years we have noticed something that has been
much more pronounced with the instant communication of our day and that is
when and where certain bird species are reported first during spring
migration. We have noticed that Tree and Violet-green Swallows, Says Phoebes
and other flycatchers along with many of the passerines are reported way to
the north of us first and it can be up to three weeks before we locate the
same species in this region. So years ago I postulated the "Migratory Back
Fill Theory" which is based on the fact that so many species are first
located hundreds of miles north of us and as the season advances these
populations gradually in fill back to the south at last arriving in our area
south of the Snake River. We are wondering if others that bird east of the
Cascades have observed this? Thank-you.
Later Mike

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Mike & MerryLynn Denny
1354 S. E. Central Ave.
College Place, WA 99324
509.529.0080 (h)

IF YOU HAVEN'T BEEN BIRDING, YOU HAVEN'T LIVED!
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