The Hawaiian common moorhen is recognized as a distinct subspecies, differing from other races in having a red blush on the front & sides of the tarsus (Taylor 1998). However, there are no evident plumage or measurement differences from forms in North America (Wilson and Evans 1890-1899; Rothschild 1900). Hawaiian common moorhens superficially resemble the related Hawaiian coot, but they are noticeably smaller, possess a red shield over their red & yellow bill, & have a white flank stripe (Schwartz and Schwartz 1949; Bannor and Kiviat 2002). They are black above & slate blue below, with underwing coverts mostly white. Their legs & feet are yellowish green, & the feet are not lobed as are the Hawaiian coot’s. The sexes are similar in appearance. Immature birds are olive-brown to grayish brown, with a pale yellow or brown bill.