Rock Sandpiper Calidris ptilocnemis breeds Alaska and adjacent Siberia and mainly winters on Pacific coast of North America; there is also a regular wintering population on Pacific coast of Japan. Vagrant Hebei. HABITAT Almost always on rocky coasts (not muddy estuaries, as Dunlin C. alpina). ID & COMPARISON Breeding resembles Dunlin, but on Dunlin patch is on belly, whereas on Rock Sandpiper black patch is on lower breast and not as solid as Dunlin. Rock Sandpiper also much more stocky than Dunlin. Juvenile has dark upperparts neatly fringed whitish and streaked breast. With its combination of slate-grey upperparts, head and neck, blotchy breast and flanks, and white underparts, Rock Sandpiper in winter resembles no other calidrid in China. BARE PARTS Feet dull yellow, in contrast to black feet of Dunlin. Mainly black bill bends downward at tip like Dunlin but is yellowish at base, unlike completely black bill of Dunlin. VOICE Mostly quiet away from breeding grounds. Short tiit contact call. — Craig Brelsford
Daniel Bengtsson served as chief ornithological consultant for Craig Brelsford’s Photographic Field Guide to the Birds of China, from which this species description is drawn.