Pectoral Sandpiper

Usually seen in small numbers during autumn migration, but not a common bird in Sonoma County even then--the bulk of migrating birds moves south on the eastern side of the Rockies. Spring migration records are rare throughout the Bay Area. Our earliest autumn arrivals usually come in the latter half of July, but most arrive later. The majority have passed through the area by early November. Perhaps most common in late September and early October, but numbers are highly variable. Absent some years. We see mostly juvenile birds. Breeds in the extreme north of Alaska and Western Canada. Winters south to South America. Named for its strong pectoral breast markings which breeding males puff up in display using underlying air sacs. Favors mudflats and marshes, muddy, grassy pond edges, flooded fields, and similar habitats. May be found near the coast or inland in suitable habitat. Shows sexual dimorphism (males noticeably larger). Usually solitary or in small groups.

A medium-sized sandpiper. The juveniles we see have a washed-out chestnut cap with fine black streaking, a pale supercilium or eyebrow, a fine white eyering, and dark lores. Rusty cheek. Bill comparatively short (black, but brownish at the base). Back has a scaly look created by rusty margins on scapulars and tertials. Back shows a pattern of white lines reminiscent of Wilson's Snipe (Gallinago delicata, see photos below)--although much less pronounced. Upper half of the underparts is heavily streaked and shows a buff wash underneath. The streaked area stops abruptly. Remaining underparts white. Leg color variable, but usually a dull yellow. Most likely to be confused with Sharp-tailed Sandpiper (Calidris acuminata), but that bird is a rarity in Sonoma County. Juvenile Sharp-tailed Sandpiper has a darker cap than Pectoral Sandpiper, a stronger white supercilium, little streaking on the breast, and a diffuse buff wash there, with no clear transition to the white underparts (compare photo below). Sharp-tailed Sandpiper may have some dark streaking at the vent never present in Pectoral Sandpiper. The best indicators are probably the washed-out look of the cap and supercilium in Pectoral Sandpiper and the difference in the streaking on the breast and the transition to the white underparts. A bird of this general description is much more likely to be Pectoral Sandpiper than Sharp-tailed Sandpiper in Sonoma County, but it's always worth checking to be sure. Sharp-tailed Sandpiper was spotted here in both 2011 and 2012. Pectoral Sandpiper may also resemble Least Sandpiper, but Pectoral Sandpiper is a much larger bird with a proportionately much longer neck.

Selected county sightings: Spring Lake (October 4, 2012, Rob O'Donnell); Ellis Creek Water Treatment Facility (September 12-25, 2012); Smith Brothers Rd. (September 22, 2012, Cory Gregory); Sonoma Mtn. Rd. (October 24, 2011, Gene Hunn); Shollenberger Park (October 11, 2011, Cory Gregory); Bodega Farm Pond (September 22, 2011, Lisa Hug); Shollenberger Park (September 11, 2011, Katherine Francone); Shollenberger Park (August 6, 2011, Bill Doyle); Shollenberger Park (October 25, 2010, Len Blumin); Carmody Rd. Pond (September 29, 2010, Lisa Hug); Shollenberger Park (September 4-10, 2010, Peter Colasanti)