Kiwi are ancient, flightless ratite birds found only in New Zealand. They are long lived, form long term monogamous pair bonds, and invest enormous resources in producing 1 to 2 chicks per year. Their unusual habits and appearance have made them national icons that are treasured by the people of New Zealand.
All five kiwi species have experienced drastic reductions in range since humans arrived in New Zealand and most kiwi populations are now small and isolated. My collaborators and I are using genetic and genomic techniques to investigate potential inbreeding effects, genetic population structure, behavior, and evolution of New Zealand’s kiwi. This information will help the New Zealand Department of Conservation (DOC) carry out their captive rearing and translocation programs to maximise genetic variation, reproductive output, and long-term persistence of kiwi.
Population structure, mating system and social dynamics of rowi
Rowi (Apteryx rowi) are the rarest kiwi species, with only a single extant population of approximately 400 individuals. Poor breeding success (approximately one third of adults do not breed) and poor hatching success (only about half of eggs in the wild produce chicks) hamper recovery of rowi and could be due to inbreeding depression. Rowi are highly aggressive and territorial, but are often found together in groups that may represent families.
We are using microsatellite markers to look at fine-scale genetic population structure and to build a pedigree of this last rowi population. Coupled with DOCs long-term data on nesting behaviour and reproductive success, we will assess the social structure and mating system of rowi and investigate patterns of juvenile dispersal.
Genetic diversity and demography of great spotted kiwi
Great spotted kiwi (GSK; Apteryx haastii) are unusual among kiwi because they tend to inhabit high altitude areas, still occupy much of their native range, and have apparently had stable population sizes for at least the last 20 years. GSK are increasingly the subject of translocation and captive incubation efforts but little is known of their ecology, genetics and demography.
We are currently using microsatellite data to assess levels of genetic diversity within GSK, determine their genetic population structure, test for genetic bottleneck effects within populations, and identify landscape factors might limit their dispersal.
Functional genomics and evolution of kiwi
We are also working to identify genes under positive selection and that might be associated with reproductive success in kiwi. We recently compared 3,774 orthologous protein coding sequences among 29 avian species representing 23 avian orders, including three species of kiwi (North Island brown kiwi (Apteryx mantelli), rowi, and LSK). We found a signal of positive selection in 77 of these orthologs with the majority (N=30) occurring on the branch separating kiwi from other avian taxa. The genes under selection are functionally diverse, including those associated with endochronal bone morphogenesis, inflammatory response, stress response, neurogenesis, innate immune response, diet induced thermogenesis, and longevity.
These datat provide clues to the nature of the divergence of paleongaths and neognaths, as well as the further evolution and divergence of the five extant species of kiwi, and provide numerous potential candidate genes for future studies.
- Helen Taylor (Otago University, New Zealand)
- NZ Department of Conservation (Rogan Colbourne, Hugh Robertson)
- Luke Dunning (University of Sheffield, UK)
- Kaitiaki o Kapiti Trust
- Waiorua Bay Trust
- Port Nicholson Block Settlement Trust
- Te Runanga o Ati Awa ki Whakarongotai Inc
- Te Atiawa Manawhenua ki te Tau Ihu Trust
- Te Runanga o Makaawhio
- Ngai Tahu
- Te Runaka o Ngati Waewae
- Ngati Rarua Atiawa
- Paparoa Wildlife Trust
- Friends of Flora
- MBC Environmental
- Arthur’s Pass Wildlife Trust
- Allan Wilson Centre for Molecular Ecology and Evolution
- NZ Ministry of Business, Innovation & Employment
- Victoria University of Wellington
- Bank of New Zealand Save the Kiwi Trust
- Birdlife International