Calidris ferrugineaCalidris ferruginea, adult summer plumage starting moult to winter plumage. San Elijo Lagoon, San Diego Co., California, USA; 4 July 1981.Source: Flickr (colour corrected and dust specks removed from original)
Calidris subminutaCalidris subminuta, adult near end of moult from summer to winter plumage. Tainan, Taiwan, 4 October 2009.Source: Flickr (cropped and levels adjusted from original).
Calidris ptilocnemisCalidris ptilocnemis, adult in summer plumage. Alaska.Source: Animal Diversity Web (misidentified as Aphriza virgata; image brightened and blue cast removed).