The 'apapane is the most abundant of the honeycreepers, and the sweetest and most varied singer. They're quite shy, and hate to be watched. From a distance their white rump ("white underpants") helps to differentiate them from i'iwi. The wings of both the 'apapane's and 'i'iwi create a whirring noise when they fly. On particularly still clear evening in the upper elevations the air can sometimes be filled with the whir of 'apapane wings.

Juveniles are mostly brown above and grey below, with occasional patches of red, gold and iridescent green.

Despite being the most abundant and widespread endemic forest bird, this is the one I've had the most difficulty getting a good photo of.

A close relative of the 'apapane is Maui's 'akohekohe, or crested honeycreeper. Another close relative was the Laysan honeycreeper, which became extinct after sailors released rabbits which destroyed Laysan's vegetation.