[birding] Comments on Nashville Warblers in the mid-Willamette Valley

[Joel Geier]

Hi Dave & all,

It's a fine point, but my comment about Nashville Warblers pertained
specifically to the mid-Willamette Valley, not the Willamette Valley as
a whole. This species is regularly much more abundant as a migrant in
Eugene -- which is situated at the top end of the Willamette Valley
ecoregion -- than at points farther north, particularly on the west side
of the Willamette. 

I haven't been following OBOL closely but it seems like the comments
about Calliope Hummingbirds are coming mostly from Eugene. I haven't
noticed that many reports in the MidValley region -- maybe 2 or 3? It's
a far cry from April 2007 when we had at least 11 local reports.

Nashville Warblers that show up on Skinner Butte in Eugene are within
the edge of their regular breeding distribution, which runs NE from the
Klamath Mountains ecoregion, and thence N through the Cascades. There's
a good reason why Skinner Butte is the premier warbler migration site in
western Oregon, since it picks up migrants from all of these regions. 

In contrast, Nashville warblers that reach northern Benton County are 40
+ miles from any regular nesting location (not counting the spotty
indications of nesting in the northern Coast Range). One wonders where
they could be headed.

Below are *all* of the spring Nashville Warbler reports from Benton
County that are in the www.birdnotes.net database, going back to 1999.

E. E. Wilson WA   (April 22, 2001)
E. E. Wilson WA   (April 21, 2005)
W.L. Finley NWR,  (April 20, 2008)
Poison Oak Hill,  (April 27, 2008)
E. E. Wilson WA   (April 27, 2009)
E. E. Wilson WA   (April 19, 2010)
Poison Oak Hill   (April 20, 2010)
Adair County Park (April 27, 2010)

Nashvilles are found a little more frequently by birders who focus on
southern Benton County, though not well represented in this database.
However, there are not that many more. Here are the *total* numbers of
low-elevation Nashville Warblers reported in the area covered by
Corvallis Audubon field notes (Benton, Linn, and s. Polk Co.), from the
seven spring seasons that I compiled these notes:

2001: 2 birds
2002: 2 birds
2003: 2 birds
2004: 0 (specifically noted no low-elevation reports)
2005: 5-6 birds (3-4 in one flock at Willamette Park)
2006: 3 birds
2007: 2 birds

I haven't kept close count this year but I can think of at least a dozen
reports off-hand. That's pretty far outside the norm compared with the
seven seasons when I was keeping track of mid-Valley reports (BTW thanks
to Rich Armstrong for doing that job this year, while Doug Robinson is
taking a well-deserved respite!).

Happy birding,
Joel

--
Joel Geier
Camp Adair area north of Corvallis