Sabine's Gull (Xema sabini), Amado Wastewater Treatment Plant, Pima County

This Sabine's Gull was discovered by Peter Salomon, John Higgins, and Dave Dunford on 07 September 2012 and photographed by Laurens Halsey the same day. 

Rare but regular (usually annual) migrant throughout Arizona, most records are from the fall.

Unmistakable.  Diagnostic upper wing pattern. Other interesting features: yellow tipped black bill, sooty gray hood with black ring at base (before the white body), and slightly forked tail.

07 September 2012, photo by Laurens Halsey