Pacific Loon (Gavia pacifica), Lakeside Park, Pima County

This Pacific Loon was discovered by David West on 18 December 2008 at Lakeside Park in Tucson.  It was first identified by Mark Stevenson and Molly Pollock on 19 December 2008 and photographed by Andrew Core the same day. 

Pacific Loon has been regular in the Lower Colorado River Valley in recent years but elsewhere in the state it is a casual transient and winter visitor. 

Although superficially similar to Common Loon, nonbreeding plumaged Pacific Loon can be identified by the straight border on the neck between the dark and the light, the dark around eye, and the diagnostic chin strap (which is not always present nor easy to see).  There are no records of the very similar Arctic Loon in Arizona but it is is eliminated in this case by the lack of white flank patches. 

19 December 2008, photo by Andrew Core

All photos are copyrighted© by photographer