Identifying sex and age of apapane and iiwi on Hawaii

Methods to determine the sex and age of Apapane (Himatione sanguinea) and Iiwi (Vestiaria coccinea) were developed on the basis of 189 museum specimens and 91 live birds captured in mist nets on the Island of Hawaii (USA). Both species retain all juvenal primaries and some juvenal secondaries and body feathers after the first prebasic molt and attain full adult plumage after the second prebasic molt. Apapane in their first basic plumage retain some buff-edged juvenal secondaries (particularly secondaries five and six) and sometimes retain a few gray-brown feathers on the head. The first basic plumage of Iiwi is characterized by secondaries 6-9 being longer and darker than secondaries 1-4 and the presence of a few yellowish juvenal body feathers with black spots at the tips. Adult male Apapane and Iiwi have longer wing, tail, exposed culmen, culmen and tarso-metatarsus lengths than females. Linear discriminant functions are presented to sex adult Apapane and Iiwi from lengths of their wing chord and exposed culmen.