Semipalmated Sandpiper (Calidris pusilla), Palo Verde Sludge Pond, Maricopa County

This juvenile Semipalmated Sandpiper was found and photographed by Kurt Radamaker on 19 September 2008 in Palo Verde. 

Semipalmated Sandpiper is a rare fall migrant in Arizona, although this has been a good year for them.

The juvenile Semipalmated Sandpiper is standing behind a juvenile Western Sandpiper giving a good comparison of birds with typical bills.  The juvenile Semipalmated Sandpiper is duller in plumage than Western, usually lacking the latter's conspicuously contrasting rusty scapulars, with short stubby bill with bulbous tip, a contrasting cap and broad supercilium and darker auriculars.  Typical Westerns have longer bills that droop and narrow toward the tip.  Unfortunately, males of both species have shorter bills than females, so male Westerns can have bills that approach female Semipalmated's, making the ID tricky. 

19 September 2008, photo by Kurt Radamaker