Willet at Toppenish NWR on April 27, 2013 ©Kevin S. Lucas

Willet at Toppenish NWR on April 27, 2013 ©Kevin S. Lucas

This appears to be "eastern" by depiction in big Sibley guide page 176
Stout bill, darker plumage pattern, dark lores, minimal wing projection.
"Eastern" Willet trait is relatively broad white band on wings.