27,000 possible but Kagu Numbers Stalled at 5,000
Latest population modelling suggests fewer than 5,000 Kagu remain on Grande Terre, but strategic habitat protection and dog control could see numbers rise dramatically
A bird like no other
The Kagu (Rhynochetos jubatus), New Caledonia’s flightless, ash-grey emblem, is one of the most distinctive island birds alive today. Unlike so many of its flightless counterparts, it has survived millennia of human presence and the introduction of predators, but only just. A new study published in the Journal of Ornithology has now provided the most detailed island-wide population estimates to date - and with them, a roadmap for saving the species.
Researchers combined fine-scale monitoring from two key reserves with large-scale habitat modelling to generate a picture of where Kagu persist, and in what numbers. The results are sobering: while the island could theoretically hold more than 27,000 birds, the real population is likely between just 2,295 and 4,985 individuals.
Habitat, soil, and dogs
The study revealed that forest type is critical in shaping Kagu densities. Rainforests growing on richer, non-ultramafic soils support the highest bird densities, whereas ultramafic soils - though poorer - offer remoter refuges. Yet even the best habitats cannot protect the Kagu from their main predator: domestic dogs. The presence of settlements, and therefore dogs, was one of the strongest predictors of Kagu absence.
Dog predation creates wide zones of ‘sink habitat’ where birds cannot persist, with the effect that much of the theoretically available forest is in reality uninhabitable. Even within protected areas, only half have any dog management in place.
Conservation gaps and opportunities
The paper’s authors warn that only 12% of predicted Kagu habitat currently lies within protected areas, and that most reserves sit on poorer ultramafic soils. Just three rainforest reserves on non-ultramafic soils exist, two of which support Kagu. Expanding these habitats is the single biggest opportunity for recovery.
The study recommends creating an additional 250 km² of protected rainforest on non-ultramafic soils. With adequate dog control, such expansion could boost the global population by as many as 9,000 individuals. “Establishing new reserves in central Grande Terre would not only safeguard the Kagu but also deliver benefits for other endangered endemics, including the Crow Honeyeater and Horned Parakeet ,” the authors argue.
The Kagu as an umbrella species
As both a cultural icon and an ecological keystone, the Kagu offers wider conservation leverage. By consuming a wide array of ground-dwelling fauna, it helps structure rainforest ecosystems. Protecting Kagu territories therefore means protecting the ecological processes on which many other species depend.
Urgency and hope
With as few as 575–1,250 breeding units left, the Kagu remains highly vulnerable. But the modelling also shows what could be achieved with strategic action. Dog control in existing reserves, community engagement to tackle free-roaming pets, and expansion of rainforest protection in the most productive soils together offer a path not only to stabilisation but to growth.
The study concludes that the fate of New Caledonia’s national bird may rest on whether conservationists and policymakers act swiftly to seize this opportunity. For a bird whose morning calls once echoed across the island’s forests, the chance to restore its voice to more valleys and ridges is within reach.
September 2025
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