Newly discovered fledglings offer hope for the Norfolk Island morepork
TWO MOREPORK OWL chicks have been found on Norfolk Island, marking the first of their kind to become fledglings in over 10 years.
It’s great news for the ageing morepork population whose last known breeding occurred in 2011. The Norfolk Island morepork (Ninox novaeseelandiae undulata) is considered one of the world’s rarest owls with less than 50 individuals remaining.
“There was an increasing possibility that most, if not all birds were now beyond breeding age,” says Dr Rohan Clark, the Head of the Ornithology and Conservation Management Research Group at Monash University.
“These chicks prove at least one pair is still young enough to breed and it adds two juveniles to the population at a time when we believe individuals in the population are otherwise all 8-plus years old.”
The entire morepork population on Norfolk is descended from a single pair of owls that first bred back in 1989. Miamiti – a female and the last pure Norfolk Island morepork and Tintola – a male New Zealand morepork – were introduced to save the population.
According to Rohan, the morepork could be suffering from inbreeding depression, but his research indicates that there’s another challenge that must be overcome.
Essential rodent control is carried out on the Island to protect the Endangered Norfolk Island robin, the Norfolk Island parakeet and other threatened forest birds. While effective in serving its purpose, the efforts are having a negative effect on moreporks consuming rodents that have fed on toxic baits.
“It is a double-edged sword because without baiting, we would almost certainly lose the robin and other species of bird on Norfolk Island to predation by invasive rodents, yet with it, we have the potential to impact on the morepork,” Rohan explains.
“We’re currently working on a separate project focused on the impacts of rodents on the other bush birds, and the behaviour of rodents more generally, so that we can robustly inform future management actions for invasive rodents to get the best outcomes for all birds.”
Despite these concerns, targeted conservation efforts for the morepork have existed on the Island since the 1980s and continues today, with researchers and local communities playing their part.
“In recent years the Norfolk community has been assisting with surveys (reporting calling birds) and Parks Australia have continued to monitor and maintain nest boxes,” Rohan says.
In 2019, two members of Rohan’s research group at Monash University set out to gain urgent insight into how many moreporks were left, what their diet currently looks like and why they hadn’t bred for so long.
This included “nest box monitoring, nocturnal surveys and radio tracking of birds to learn about home range, pair behaviour and other elements of their biology that are important to inform conservation management.”
Further on-site research is currently on hold due to COVID-19, but Rohan hopes his researchers will be back on Norfolk Island in spring this year.