About 5% of common Australian wild birds including kookaburras and lorikeets could have undergone a “sex reversal” where their genetic sex does not match their reproductive organs, according to a new study.

The study is thought to be the first to find widespread sex reversal across multiple wild bird species, but the cause of the phenomenon is not yet known.

The results suggest sex reversal is more common in wild birds than previously thought, and have raised concerns about the potential impact of chemicals that can disrupt hormones in animals.


Researchers tested 480 birds across five common species that had died after being admitted to wildlife hospitals in south-east Queensland.