We describe the history of Motukawanui, the largest island of the Cavalli Islands, off New Zealand’s Northland east coast, and report on a survey of terrestrial vertebrates undertaken in February 2020. We compare our findings to the previous published survey conducted in December 1979–January 1980. Over the last 40 years, the island’s landscape has changed dramatically from one of farmland to predominantly native forest. As a result, the habitat has shifted toward supporting a larger assemblage of endemic and native birds, and away from supporting those that are non-native. Kiore, or Pacific rats (Rattus exulans), remain abundant across the island, though densities are lower compared to estimates of the previous survey. The richness of reptile species also appears to have declined over the past few decades. Overall, we suggest Motukawanui is a relatively straightforward island from which to eradicate rats. Such an eradication would require approval from local iwi but would directly contribute to meeting interim goals of the Predator Free 2050 initiative.
The authors thank the kaumātua roopu of Ngāti Kura for permission to visit the island, Rod Hitchmough for information on reptile species, Maud Quinzin for help in rat trapping, Rod Brown for information on restoration planting, and Graeme Taylor for providing a copy of the unpublished DOC report on the Cavalli Islands. Z.T.C. personally thanks Dean Wright (of Dean Wright Photography; https://www.deanwright.co.nz/) and Stephen Western (of Stephen Western Photography; https://stephenwestern.smugmug.com/) for help in providing photo comparisons. TriOceans provided transport to and from the island.
The fieldwork of this study was independently funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 747120 awarded to T. W. B. Research was performed under the University of Auckland animal ethics R2095 and wildlife authority 67914-DOA and research and collection authority 67915-RES. Funding was awarded to Z. T. C. by the New Zealand Government through a New Zealand International Doctoral Research Scholarship.
- Ecological management
- invasive species
- Pacific rat
- Predator Free 2050
- Animal Science and Zoology