# Kakapo — Facts, Threats & Conservation

*Strigops habroptilus (Gray, 1845) — family Strigopidae*

> The kākāpō (Strigops habroptilus) is the world's only flightless parrot and the heaviest, a nocturnal New Zealand species now confined to predator-free offshore islands where every individual bird is named, microchipped and monitored.

**IUCN status:** Critically Endangered — every living bird is individually named and monitored  ·  **WARN range:** New Zealand — predator-free offshore islands only, Extinct across the mainland

## Quick facts
| Fact | Value |
| --- | --- |
| Weight | Up to ~4 kg — heaviest parrot |
| Flight | Flightless — the only such parrot |
| Activity | Nocturnal |
| Mating system | Lek — males boom, females choose |
| Breeding trigger | Rimu mast fruiting, every 2–4 years |
| Range | Predator-free New Zealand offshore islands only |

## Scientific classification
- **Kingdom:** Animalia
- **Phylum:** Chordata
- **Class:** Aves
- **Order:** Psittaciformes
- **Family:** Strigopidae
- **Genus:** Strigops
- **Species:** Strigops habroptilus

## Conservation status
- **Status:** Critically Endangered
- **Population:** A few hundred individuals, all individually known
- **Trend:** Increasing under intensive management
- **Assessed:** 2021
- **CITES:** Appendix I
- Genetic diversity is critically low. Recovery is limited less by breeding success than by the availability of predator-free islands large enough to hold more birds.

## Key facts: Kakapo
- Kākāpō are the only flightless parrots and the heaviest parrot species alive.
- Males 'boom' from excavated bowls to attract females — a lek mating system unique among parrots.
- Breeding is tied to mast fruiting of rimu trees, so it happens only every two to four years.
- Freezing when threatened worked against aerial hunters and failed against introduced mammals.
- The entire species lives on predator-free offshore islands under intensive management.
- Every living kākāpō is named, microchipped and individually monitored.

## Booming: a lek in the dark
Male kākāpō dig shallow bowls in the ground, position them where the acoustics carry, and inflate a thoracic air sac to produce a deep, resonant boom repeated for hours through the night. The low frequency travels several kilometres across valleys but is notoriously hard to locate, which is part of the point.

Females walk in from a distance, assess the displaying males, and choose. This is a lek system — males cluster and display, females select and then raise the chicks alone — and no other parrot in the world does it.

## Breeding on the rimu cycle
Kākāpō breed only when rimu trees mast-fruit, which happens every two to four years. Females need that fruit glut to raise chicks, and in non-mast years they simply do not breed.

That evolutionary caution is sensible for a long-lived bird in a stable environment and disastrous for a species in crisis: recovery can only proceed in bursts. Conservation managers now supplement food to trigger and support breeding, monitor nests continuously, and hand-rear chicks where necessary — measures that would be extreme for almost any other species and are routine here.

## Why the defence failed
New Zealand's land birds evolved with no mammalian predators. The threats were aerial, so freezing and relying on cryptic green plumage was an excellent strategy. Then people arrived, bringing rats, cats, stoats and possums.

Against mammals that hunt by scent, a strongly scented bird that freezes on the ground and cannot fly is close to defenceless — and a nesting female leaves eggs and chicks unattended while feeding. Kākāpō disappeared from the mainland entirely. Every surviving bird was eventually relocated to islands cleared of introduced predators.

## Managed to the individual
The recovery programme tracks every bird by transmitter, records genetics across the whole population, supplements food, monitors nests with cameras, and intervenes when a chick is failing. Genetic diversity is critically low — the entire species descends from a small remnant — so pairings are managed to preserve what variation remains, and the genome of essentially every individual has been sequenced.

The population has grown from a low point of a few dozen to a few hundred. It remains Critically Endangered, and the constraint is now space: predator-free islands large enough to hold more birds are scarce, which makes further predator eradication the central task.

## What WARN does
WARN publishes free, sourced species education including the extreme end of conservation practice. The kākāpō shows both what is achievable when a species is managed bird by bird, and how expensive and precarious recovery becomes once a population falls that far.

If this guide helps you understand wildlife and the pressures it faces, a gift to WARN supports habitat protection and free public education in our partner countries.

## Frequently asked questions: Kakapo
### Can kākāpō fly?
No. The kākāpō is the world's only flightless parrot. It has short wings used for balance and for breaking a fall when climbing down from trees, but it cannot achieve powered flight.

### How many kākāpō are left?
A few hundred — the population is small enough that every living bird is individually named, microchipped and monitored. Numbers have risen from a low point of a few dozen, but the species remains Critically Endangered.

### What is kākāpō booming?
The male's mating call. He excavates a shallow bowl in the ground, inflates a thoracic air sac and produces a deep boom repeated for hours at night. The low frequency carries for kilometres but is very hard to pinpoint. Females travel in to assess displaying males.

### Why do kākāpō breed so rarely?
Breeding is tied to mast fruiting of rimu trees, which occurs only every two to four years. Females need that abundance to raise chicks and will not breed in other years, so population recovery can only happen in bursts.

### Why did kākāpō become so endangered?
New Zealand's birds evolved without land mammals, so the kākāpō's defence was to freeze and rely on camouflage. That fails completely against introduced rats, cats and stoats, which hunt by scent. Being flightless, ground-nesting and strongly scented left it defenceless once mammals arrived.

## Sources
- [IUCN Red List — Strigops habroptilus](https://www.iucnredlist.org/species/22685245/129751169)
- [CITES Appendices](https://cites.org/eng/app/appendices.php)

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Full guide: https://worldanimalrescuenetwork.org/wildlife-guides/kakapo