Biologists have uncovered a spotted New Zealand bellbird (Anthornis melanura) in Karori’s Zealandia eco-sanctuary that exhibits features and behavior of both male and female members of the species.
The transgender korimako tested female by its DNA but acts like a male. It has a mix of each sex’s plumage. It could be due to a hormonal imbalance or it could be the reaction to an incomplete moult, states Ben Bell, moult expert at Victoria University.
This is the first species that Zealandia staff has discovered showcasing an unusual gender mix. A. melanura are about the size of a sparrow, with dark olive-green plumage and red eyes. Males and females look alike, except that the male is tinted blue around its beak and eyes, whereas the female has a white stripe extending back from the bill.
The bird was hatched in 2011, and is 18 months old now. The bird’s calls have also been mixed. However, the mixed song is less unusual than the plumage and the behavior. The bellbird is at risk from mammalian pests as it often forages in unprotected habitat beyond the northwestern scarp of Zealandia.
This isn’t the first transgendered bird to be discovered. Both transgendered and homosexual birds have been documented before, but this is the first time this trait has been discovered in A. melanura.