The Oahu creeper is a small (11 centimeters, 4.3 inches in length) sexually dichromatic Hawaiian honeycreeper endemic to the island of Oahu. Female and immature birds are gray to grayish green above and yellowish white below, and usually have two prominent white wing bars. Males are olive-green above and golden yellow below, with a yellow forehead and superciliary line, a dark eye line and do not have wing bars (USFWS 2010). The bill is straight, relatively short, dark above, and pale below (Shallenberger and Pratt 1978; USFWS 2006). Oahu creepers apparently formed foraging flocks during parts of the year. Perkins (1903) reported that as many as a dozen creepers often were seen together, and Swedberg (in Shallenberger and Pratt 1978) reported a flock of 30 to 50 birds at Poamoho Trail in September 1968, some of which were collected and proved to be Oahu creepers.