Background

This measure relates to indicator 1.4.2 – Security of threatened and at risk taxa.

The kākāpō is one of Aotearoa New Zealand’s unique national treasures. However, this Nationally Critical bird is found on only four of New Zealand’s offshore islands, with a population size of almost 250 individuals and major threats of infertility, disease and low genetic diversity. DOC has been closely monitoring kākāpō populations since 1990, with a dedicated recovery programme formed in 1995. Intensive conservation management has more than quadrupled the size of the population since then, and from 2016-2023 the population increased by 100% as a result of large rimu masts in 2016, 2019 and 2022.

A male kākāpō on Whenua Hou in 2022. Credit: Andrew Digby.

What did we measure?

The entire kākāpō population has carried radio transmitters and been closely monitored since 1990 to allow accurate determination of the population demographics.

What did we find?

• There was no kākāpō breeding in 2025.
• The kākāpō population consists of 242 individuals as of 30/6/2025 (Figure 1).
• The population sex ratio and age structure remains well balanced with good numbers of males and females and a range of ages (Figure 2).
• Two kākāpō populations were temporarily disestablished: Hauturu-o-Toi and Pearl Island. The kākāpō from these sites were moved to southern islands.
• There were four adult and one juvenile kākāpō deaths from July 2024 - June 2025 (Figure 3).
• Research projects are investigating many areas relating to kākāpō management, including disease, genetics, microbiology, habitat use, and diet. This included a vaccination trial for highly pathogenic avian influenza.
• A new kākāpō transmitter was deployed after several years of development, providing greater battery life and improved monitoring capabilities.

Figures

Figure 1: Changes in the kākāpō population (adults and juveniles combined) since 1990. Population totals apply to 1 January each year.

Figure 2: Age structure and sex ratio of the kākāpō population as of 30/6/2025. For age class definitions, see below.

Class	Age range
Adult	> 5 years
Juvenile	150 days - 5 years
Chick	< 150 days

Figure 3: Annual number of kākāpō deaths since 1991 (calendar years).

Data quality

This measure is classified as a partial measure of high accuracy. It complies with the data quality guidelines used in New Zealand’s Environmental Reporting Series.

Intensive management and low numbers of individuals allow regular and complete censuses of the entire population to be made. Therefore, the key demographic parameters reported on are extremely accurate.

Glossary of terms

Nationally Critical is a species conservation status within the New Zealand Threat Classification System, defined as “most severely threatened, facing an immediate high risk of extinction”.

Additional resources

Lee, W.; McGlone, M.; Wright, E. 2005: Biodiversity inventory and monitoring: a review of national and international systems and a proposed framework for future biodiversity monitoring by the Department of Conservation. Landcare Research Contract Report LC0405/122 for the Department of Conservation, Wellington (unpublished). 213 p.

McGlone, M.; Dalley, J. 2015: A framework for Department of Conservation inventory and monitoring: intermediate outcomes 1–5. Landcare Research Contract Report LC2427 for the Department of Conservation, Wellington (unpublished). 75 p.