The Norfolk Island Morepork owl is again facing a serious risk of extinction, with researchers warning that inbreeding is limiting reproduction in a population descended from a single female. About 25 birds are thought to remain on the island, according to the supplied report from ABC News Australia.
The species nearly disappeared in the 1980s. In 1988, a male Morepork from New Zealand was transported to Norfolk Island, and the population later increased to about 50 birds by the late 1990s. Norfolk Island science ranger Allie Andersen said reproduction increased after that intervention, with more nesting and young birds being recorded.
Andersen said the population’s growth has since stagnated, which she linked to inbreeding. “Every single owl that we have now is derived from just those two individuals,” she said. Some years produce no observed breeding, while a 2021 study found about 26 owls remained, many believed to be from an older generation.
Monash University ornithologist Rohan Clarke said there may be only one breeding pair among roughly 15 pairs on the island. He said the number of young being produced was very small and that infertility and other reproductive problems were characteristic of populations affected by severe genetic bottlenecks. Clarke said the window for action could be measured in years.
Researchers are considering bringing additional Morepork owls from New Zealand, where the species is listed as “not threatened” by the country’s Department of Conservation. The proposed translocation is intended to increase genetic diversity, but it has not yet been approved.
Community consultations on Norfolk Island have been completed, while further discussions are required with Māori traditional custodians and environmental agencies. Parks Australia said substantial ecological, genetic and practical challenges, including potential biosecurity risks, must be addressed before the plan could proceed. The owl also faces a risk of secondary poisoning from chemicals used against rats and house mice. Andersen said the community remained concerned but hopeful, citing ongoing research and conservation partnerships.