Apapane

ʻApapane are small at 13 cm (5.1 in) when fully grown. They are sexually dimorphic in size: male ʻapapane have a mass of 16 g (0.56 oz), while females average 14.4 g (0.51 oz). Adult ʻapapane are overall bright crimson, with distinct white undertail-coverts and lower abdomen feathers. They have black primaries and retricies. Juvenile ʻapapane are yellow-brown and gray, with the same white plumage as adults, and molt into crimson plumage over the course of two years. 'Apapane are often seen in a tail-up posture, showing off their white feathers. Voice: ʻApapane are active singers, including in flight. There is considerable variation in their calls and songs, but phrases are often repeated. They are known to sing at a perch for 10-30 second intervals, and their song may include repeated squeaks, whistles, rasps, melodic trills, and clicking sounds.