Kākā nest box programme

Location: Wellington, Aotearoa New Zealand
Project type: Urban wildlife restoration and species management programme
Delivery/lead organisations: Zealandia Te Māra a Tāne; Greater Wellington Regional Council; Wellington City Council (supporting partners)
Date/period: 2002 – present
Scale: Site / Urban / Landscape
Primary system or theme: Native birds; urban biodiversity management

Context

Why this site matters
The North Island kākā (Nestor meridionalis septentrionalis) was locally extinct in the Wellington region by the late twentieth century due to habitat loss and predation by introduced mammals. 1, 2 The establishment of Zealandia as a predator-fenced ecosanctuary enabled reintroduction within an urban setting, supported by intensive management interventions. 3

Challenge or constraint

What wasn’t working/what needed to change
Kākā are obligate cavity nesters reliant on large tree hollows, which are scarce in fragmented and secondary forests common in urban and peri-urban landscapes. 1, 2 Introduced mammalian predators significantly reduced nesting success in unmanaged environments, limiting population recovery even where nesting cavities were present. 4

Intervention

What was done
Artificial nest boxes were deployed as part of a broader kākā recovery programme to increase nesting opportunities and reduce predation risk.

Key components

  • Installation of artificial nest boxes within Zealandia and selected urban green spaces 3
  • Predator-exclusion design features (e.g. metal collars, controlled access points) 5
  • Integration with intensive predator control and supplementary feeding programmes 3
  • Long-term monitoring of occupancy and breeding success 3, 4

Implementation notes

Design and delivery considerations

  • Nest boxes were introduced at the outset of reintroduction to enable early breeding and monitoring 3
  • Approximately 100 nest boxes are actively maintained within Zealandia 3
  • Expansion beyond the sanctuary required coordination with pest control initiatives in urban parks 3
  • Nest boxes outside predator-managed areas showed reduced effectiveness 4, 6
  • Ongoing maintenance and monitoring are required to manage hygiene, wear, and predator adaptation

Outcomes

Observed or reported outcomes

  • Consistent occupation of nest boxes within Zealandia during breeding seasons 3
  • Higher breeding success in predator-managed areas compared with unmanaged mainland sites 4
  • Rapid population growth from six founders in 2002 to several hundred birds regionally by the late 2010s 3
  • Earlier-than-expected breeding by young females within the sanctuary population 7

What is plausible but unmeasured

  • Increased nesting opportunities may have accelerated population establishment in urban-adjacent habitats
  • Nest boxes likely improved monitoring efficiency and adaptive management capacity

Evidence and limits

What the evidence supports
Evidence indicates that artificial nest boxes contribute to improved nesting success for kākā when combined with sustained predator control and active management. 4, 5

Key limitations or uncertainties

  • Nest boxes alone do not offset high predator densities in unmanaged urban areas 4, 6
  • Outcomes are strongly context-dependent on predator control, food availability, and habitat structure
  • Social impacts of urban kākā expansion (e.g. property damage and human–wildlife conflict) require active management 7–10
  • Transferability to other cities depends on governance capacity for long-term predator control, monitoring, and maintenance 3, 4

Relevance to design practice

  • Provide secure nesting habitat as part of an integrated package (predator control + nesting + monitoring), not as a stand-alone habitat add-on 3–5
  • Avoid relying on nest boxes where predator control and maintenance access cannot be sustained 4, 6
  • Treat nest boxes as operational assets with lifecycle obligations (inspection, cleaning, repair, data collection) 3, 7, 9

References

  1. Beggs, J. R., & Wilson, P. R. (1991). The kākā Nestor meridionalis, a New Zealand parrot endangered by introduced wasps and mammals. Biological Conservation, 56, 23–38.
  2. Wilson, P. R., Karl, B. J., Toft, R. J., Beggs, J. R., & Taylor, R. H. (1998). The role of introduced predators and competitors in the decline of kākā populations in New Zealand. Biological Conservation, 83, 175–185.
  3. Armstrong, I. (2022). Life in the city: The influence of the urban environment on behaviour and spatial distributions in North Island kākā. Master’s thesis, Victoria University of Wellington.
  4. Moorhouse, R. J., Greene, T. C., Dilks, P. J., et al. (2003). Control of introduced mammalian predators improves kākā breeding success. Biological Conservation, 110, 33–44.
  5. Greene, T. C., & Jones, A. (2003). Observed responses of captive stoats (Mustela erminea) to nest boxes and metal collars used to protect kākā nest cavities. New Zealand Journal of Ecology, 27, 49–56.
  6. Fea, N., Linklater, W. L., & Hartley, S. (2020). Responses of New Zealand forest birds to management of introduced mammals. Conservation Biology, 35, 35–49.
  7. Breed, C. (2024). Wellington kākā culture: Life, death and relationality in a multispecies city. Doctoral thesis, Victoria University of Wellington.
  8. Charles, K. E., & Linklater, W. L. (2013). Behaviour and characteristics of sap-feeding North Island kākā in Wellington, New Zealand. Animals, 3, 830–842.
  9. Linklater, W. L., Chapman, H. M., Gregor, A., et al. (2018). Initiating a conflict with wildlife: The reintroduction and feeding of kākā, Wellington City, New Zealand. Pacific Conservation Biology, 24, 360–370.
  10. Gouws, J. (2020). The human-dimensions ecology of parrots reintroduced to a city: The kākā (Nestor meridionalis) of Wellington, New Zealand. Doctoral thesis, Victoria University of Wellington.