A population of South Island robin (kakaruai) near Dunedin faces local extinction without intervention. A recent study indicated a concerning male-to-female ratio of 10-1 in Silver Stream, northwest of Dunedin.
Manaia Permain-Fenton, a researcher and ecologist at the University of Otago, described this situation as a rare real-time observation of the extinction process of a taonga (treasured species). Historically widespread, kakaruai now exist in only two wild populations on the east coast of the South Island.
Despite the loud calls from males, which suggested a larger population, Permain-Fenton noted that they were solitary bachelors. She reported, “In Silver Stream, there was only one female that I found that actually survived to the end of the season.”
Predation, particularly by rats, and habitat destruction by deer and pigs have severely impacted the species. While there was previously smaller-scale predator control in Silver Stream, it was insufficient to sustain the population.
Permain-Fenton emphasized the importance of awareness regarding the kakaruai’s plight, stating, “Native species could not be saved without predator control and collaboration.”
Over a decade ago, kakaruai were translocated from Silver Stream to Orokonui Ecosanctuary, where they have thrived due to the absence of predators. Advocacy lead Taylor Davies-Colley mentioned that the population had increased significantly, with estimates of over 200 breeding pairs.
However, he raised concerns about the lack of kakaruai outside the ecosanctuary, attributing this to the predation risks in the surrounding environments. “These birds on the inside grow up in a naive environment,” he added.
Steeds from Predator Free Dunedin noted ongoing efforts to control predators in nearby areas, though funding is currently limited to mustelids and possums.