Source: NZ Department of Conservation
The future is looking brighter for the Karure/Kakaruia/Chatham Islands black robin, with ongoing monitoring and research showing encouraging signs of recovery across the species’ range while also helping guide future conservation decisions.
Translocation helping turn around Mangere population
In 2022, ten female black robins were moved from Hokorereoro/Rangatira Island to Maung’ Rē/Mangere Island to address a heavily male-biased population and reduce the risk of local extinction. At the time, predictive modelling indicated the Maung’ Rē /Mangere population faced a high extinction risk.
Five breeding seasons later, the results are promising. At the start of the 2025/26 breeding season, Maung’ Rē/Mangere supported 39 adult black robins (21 males and 18 females), with eight chicks fledging during the season. More than half of the birds on the island now have Rangatira ancestry, and the population has a much healthier balance of males and females.
Research led by Dr Liz Parlato from Massey University and Dr Tammy Steeves from the University of Canterbury shows that birds with Hokorereoro/Rangatira ancestry have higher survival and reproductive success than birds with Maung’ Rē/Mangere ancestry alone. Population modelling indicates the translocation has had an overall positive effect on population growth in the years since release.
Hokorereoro/Rangatira remains strong, but growth is slowing
New population modelling completed this year has provided valuable insights into the only other black robin population on Hokorereoro/Rangatira Island. The analysis found the population increased from an estimated 253 birds in 2011/12 to around 340 birds at the start of the 2025/26 breeding season.
While the population remains healthy, the modelling found evidence that growth may be slowing as the island approaches its carrying capacity. Increasing population density appears to be reducing productivity, with fewer juvenile birds being produced per breeding female than in earlier years. Future increases will possibly be constrained by available habitat and resources.
These findings highlight the importance of establishing and maintaining additional populations on other islands to support the long-term resilience of the species.
Understanding what black robins need to thrive
Alongside population monitoring, new research is helping build a clearer picture of black robin habitat requirements and food availability across the Chatham Islands.
A University of Waikato study led by Caleb Teague examined invertebrate communities and black robin feeding behaviour across several island sites. Researchers collected more than 2,400 invertebrates and found predator-free habitats supported significantly more large-bodied ground-dwelling invertebrates, an important food source for black robins.
The study confirmed that black robins are opportunistic feeders, with beetles, flies and wētā making up more than 70 per cent of their diet. Cave wētā were detected in almost every sample analysed, highlighting their importance as prey. Caleb also found that more than 80 per cent of black robin foraging occurs on or near the forest floor.
While prey availability is important, factors such as nest cavity availability, territory quality and vegetation structure also play a significant role in determining habitat suitability.
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Supporting future conservation decisions
Together, these projects are improving our understanding of what drives black robin population growth, survival and habitat use.
The findings are already helping inform future translocations, habitat restoration priorities and population management decisions.
From a species once reduced to just a handful of individuals, the karure/kakaruia/black robin continues to demonstrate the value of long-term conservation, collaboration and science-based management.
Learn more about the Karure/Kakaruia/Chatham Islands black robin.
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Original source: https://nz.mil-osi.com/2026/09/08/black-robin-recovery-gains-momentum/