Here is a reference photo I scanned from "The Shorebird Guide" by O'brien, Crossley, and Karlson. It shows Wilson's and Semi-p Plover together. Note that if turned around, the short bill of Semi-p would not reach the eye, being less than half the width of the bird's head. The bill on Wilson's if turned around would reach well past the eye and more than half the width of the head. Otherwise, as shown in the photo, the two can be very similar.
http://www.flickr.com/photos/22183060@N08/9426949119/ Dave Wheeler N. Syracuse, NY -- Cayugabirds-L List Info: http://www.NortheastBirding.com/CayugabirdsWELCOME http://www.NortheastBirding.com/CayugabirdsRULES http://www.NortheastBirding.com/CayugabirdsSubscribeConfigurationLeave.htm ARCHIVES: 1) http://www.mail-archive.com/cayugabirds-l@cornell.edu/maillist.html 2) http://www.surfbirds.com/birdingmail/Group/Cayugabirds 3) http://birdingonthe.net/mailinglists/CAYU.html Please submit your observations to eBird: http://ebird.org/content/ebird/ --