Solved: the mystery of the baby-killer parrots

Why do female Eclectus parrots kill their sons as soon as they hatch? While humans sometimes “sex select” their babies, no other species is known to kill its own children.

Eclectus parrots, from PNG and northern Cape York, are about the size of a sulphur crested cockatoo and nest in tree trunk hollows. The research team found that infanticide was only happening in certain types of nest hollows.

“It was the adult females who had poor hollows who would often get rid of the male, if they laid a male and a female chick. It was always a younger brother, and in doing that they could speed up the development of the older female chick,” researchers said.

As female Eclectus chicks fledge up to seven days earlier than their male siblings, the adult females with poor nest hollows stand a better chance of reproductive success concentrating their maternal efforts on female chicks.

Read more at Australian National University