Hawaiian Stilt reclassified from endangered to threatened
The endemic Hawaiian waterbird has been downlisted after its population recovered from around 200 birds to more than 1,500, although it remains dependent on active conservation.
Hawaiian Stilt has been reclassified from endangered to threatened in recognition of more than five decades of conservation work that has helped bring the endemic waterbird back from the brink of extinction.
The US Fish and Wildlife Service published its final decision on 20 July, with the revised status due to take effect on 19 August 2026. A species-specific rule will retain important legal protections while allowing conservationists greater flexibility to undertake habitat restoration and other work intended to support the bird’s recovery.
Known in Hawai‘i as Ae‘o, Hawaiian Stilt Himantopus mexicanus knudseni is an endemic subspecies of Black-necked Stilt. It inhabits shallow wetlands, waterways and coastal mudflats, where it feeds and nests on exposed or sparsely vegetated ground.
The population fell to an estimated 200 birds during the 1940s following overhunting, extensive wetland loss and the arrival of invasive mammalian predators. Federal protection, predator control, habitat restoration and water-level management subsequently helped numbers recover to more than 1,500 birds.
A new study published in Ornithological Applications examined more than five decades of reproductive data to assess how the population had responded to conservation. Researchers compiled information from 30 published and unpublished sources covering 2,056 nests and 1,051 fledglings at nine wetlands on O‘ahu between 1963 and 2020.
The results showed modest improvements in both nesting success and fledging success. Across the study sites, an average of 71% of nests produced at least one chick, while 44% of hatched chicks survived to fledging.
Both measures were estimated to have increased by around 0.4% annually between 1970 and 2020, suggesting that management measures have reduced complete nest failures and improved chick survival. However, clutch size, hatching success, nest density, fledgling density and overall reproductive success did not show comparable increases.
There were also substantial differences between individual wetlands. The strongest results were recorded at sites where invasive predators were excluded and water levels were managed to reduce the risk of nests being flooded or drying out.
Despite its improved status, Hawaiian Stilt remains reliant on continuing intervention. Its remaining threats include invasive predators, unsuitable water levels, non-native vegetation, disease, urban development, water extraction, pollution and the loss of coastal wetlands through sea-level rise.
Lead author Jessica Idle described the bird as a conservation success story still in progress. “Downlisting doesn’t mean the work is done,” she said. “It means the work is paying off.”
The researchers concluded that expanding protected and actively managed wetlands, alongside improved monitoring of chicks, juveniles and adult survival, will be essential if the population is to continue growing towards full recovery.
July 2026
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