Rock Sandpiper Identification, All About Birds, Cornell Lab of Ornithology

Nonbreeding adult/immature

Stocky, short-legged sandpiper with a dropping bill that is yellow at the base. Nonbreeding birds are pale gray above with spotting on the breast.

Breeding adult

Stocky, short-legged sandpiper with a dropping bill that is yellow at the base. Breeding birds have a pale head, chestnut markings on the back, and a dark belly patch.

Breeding

Males and females may incubate the eggs alone, or both parents may share the responsibility. Clutch sizes are generally between one and four eggs.

Nonbreeding adult/immature

Plumage brightest varies from darkest in the Aleutian Islands to palest in the Pribilof Islands. Nonbreeding birds are grayish above with gray spotting below.

Juvenile

Juveniles have cinnamon edging on their back feathers and brownish spotting on the breast.

Juvenile

Juveniles have cinnamon edging on their back feathers and brownish spotting on the beast.

Molting adult

Adults molting from breeding plumage to winter plumage show a combination of characteristics. Stocky, short-legged stature and dropping bill help with identification.

Nonbreeding adult/immature (with Black Turnstone)

Often seen huddling together on rocky coastlines or along breakswalls. Note stocky, short-legged stature and dropping bill that is yellow at the base.