New study has important implications for the survival of the endangered kākāpō parrot

New study has important implications for the survival of the endangered kākāpō parrot

Source: Wikimedia, CC BY 2.0 Chris Birmingham, 2012. (

A new study published in peerJ has provided crucial insight into the factors affecting the fertility of the critically endangered kākāpō, a flightless parrot species native to New Zealand.

The study’s findings have important implications for conservation management efforts aimed at improving the slow population growth of this species and underscore the need for a balanced approach to conservation management that considers both the short-term benefits and the potential long-term impacts of the hand rearing and other management strategies.

The results have immediate applications in kākāpō conservation management:

  1. Hand-rearing of males should be limited as much as possible; a reversal of previous strategies that prioritized keeping female chicks in nests.
  2. Population densities should be maximized so that there are enough male leks to ensure adequate mate choice for the females, but so that the female-to-male sex ratio is kept as high as the habitat will allow.
  3. Artificial insemination should also be continued to ensure sufficient sperm competition and increase founder representation.

Low productivity limits population recovery of the kākāpō (Strigops habroptilus), as infrequent breeding, high sterility, and low breeding success hamper conservation efforts. Kākāpō breeding occurs irregularly, synchronized with the mass fruiting (masting) of certain tree species, notably the rimu tree (Dacrydium cupressinum), which occurs only every 2–4 years.

Conservation strategies for wild endangered species like the kākāpō rely on improving survival and productivity to increase population growth. Methods such as habitat restoration and predator control are used to improve survival, but it is often reproductive performance issues that limit recovery the most. Hand-rearing, in which animals are raised in captivity by humans, is often used in endangered species conservation programs, primarily to increase productivity by improving survival during development to maturity.

The study used Bayesian mixed models to examine the relationship between hand-rearing, other environmental factors, and clutch fertility in the kākāpō.

The outcome study suggests that some aspects of maintenance management may have unintentionally impacted kākāpō productivity by reducing clutch fertility. The management intervention of hand-rearing has undoubtedly increased chick survival but reduced clutch fertility. The sex difference in this effect indicates that hand-rearing affects copulation behavior more in males than in females, consistent with imprinting behavior found in hand-reared male kākāpō but not female kākāpō.

The research also found that female copulation behavior—including polyandry and repeated copulations—is likely driven by high levels of sperm competition in kākāpō to improve the likelihood of fertilization.

The results of this study highlight the importance of collecting detailed longitudinal data and examining similar effects of hand-rearing and sex ratios in other threatened bird species.

About the kākāpō

Up to 64 cm (25 in) long, these flightless birds have finely mottled yellow-green plumage, a distinct facial disc, forward-facing owl-style eyes with surrounding discs of specially textured feathers, a large gray bill, short legs, large blue feet, and relatively short wings and tail: a combination of features that make it unique among parrots. It is the world’s only flightless parrot, the world’s heaviest parrot, and is also nocturnal, herbivorous, visibly sexually dimorphic in body size, has a low basal metabolic rate, and lacks male parental care. It is the only parrot to have a polygynous Lek breeding system. It is also possibly one of the longest-living birds in the world, with a reported lifespan of up to 100 years.

The kākāpō is in danger of extinction; The total known adult population consists of 249 living individuals, all named and tagged, and restricted to four small islands off the coast of New Zealand that have been cleared of predators.

The name kākāpō is Maori and means “night parrot”.

More information:
Andrew Digby et al, Hidden effects of conservation management on the fertility of the endangered kākāpō, peerJ (2023). DOI: 10.7717/peerj.14675

Listen to the kākāpō calls: … ds/birds-az/kakapo/

Journal Information:

Citation: New Study Has Important Implications for Survival of Critically Endangered Kākāpō Parrot (2023 February 3) Retrieved February 3, 2023 from -critically-endangered.html

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