Federal wildlife officials have reclassified the aeʻo, or Hawaiian stilt threatened, shifting the native waterbird from endangered after decades of conservation work boosted its numbers. The move has drawn praise for progress and concern that protections may be eased too soon.
The U.S. Fish and Wildlife Service changed the bird’s status earlier this month, noting gains from roughly 200 birds a century ago to an estimated population near 2,000 in recent years. Overhunting and the loss of coastal wetlands once pushed the species to the brink. Listed as endangered in 1970, the aeʻo benefitted from predator control and the restoration of core wetland habitats across the islands.
Researchers estimate the population has grown nearly tenfold, approaching 2,000 individuals. Melissa Price, a University of Hawaiʻi associate professor who has analyzed population trends, described the stilt as striking and bold, noting its aggressive nest defense behavior.
The recovery stands out in a state often called the endangered species capital of the world. Hawaiʻi still has nearly 500 species on the Endangered Species Act, many of them declining. Beyond the aeʻo, only a few native species have seen status upgrades or delistings in recent years, including the nēnē and the ʻio.
Jonee Peters, executive director of the Conservation Council for Hawaiʻi, said the aeʻo’s gains underscore that Endangered Species Act protections work. However, she argued the shift to threatened is premature given ongoing risks from climate change, habitat loss and invasive predators. She also pointed to recent federal policy changes that end blanket protections for species newly classified as threatened, warning that reduced safeguards could allow backsliding.
In announcing the change, the Fish and Wildlife Service said the prior across-the-board protections for newly threatened species were burdensome and incorrect to apply. Under current rules, officials must also weigh economic impacts when designating critical habitat. Price supported the stilt’s reclassification and said while pro-development policies could harm other species, she does not expect the aeʻo to be affected under its new status.
Hawaiian stilt threatened status and working lands
The aeʻo’s steep decline last century stemmed largely from water diversions for industrial agriculture that drained wetlands. The loss of loʻi kalo and other traditional agricultural wetlands, once tended by Native Hawaiians, also removed important nesting areas.
Today the birds often coexist with farmers and community groups restoring loʻi and wet fields. Price said the stilts sometimes trail behind workers who weed and clear invasive grasses, snatching up insects turned up from the mud. Studies suggest the birds are more at ease around regular loʻi stewards than occasional visitors.
Downlisting can reduce restrictions that complicate farm and restoration work when stilts nest in active fields. Price said the change provides flexibility so routine management, like weed pulling, can continue without undue stress, while still safeguarding nests and chicks.
The aeʻo will continue to rely on protected wetlands that are not affected by recent federal rule changes, including Hanalei National Wildlife Refuge on Kauaʻi, James Campbell National Wildlife Refuge and the Hāmākua and Kawainui marshes on Oʻahu, and Kanahā Pond State Wildlife Sanctuary on Maui. A recent study led by U.S. Geological Survey researcher Eben Paxton estimated the population averaging as high as 1,932 birds.
A federal recovery plan for Hawaiian waterbirds recommended reclassification to threatened once the aeʻo showed a stable or increasing population that did not fall below 2,000 birds, along with protections for core and many supporting wetland sites. Peters said her organization believes the benchmarks have not been fully met, though she did not specify which ones.
Racing against time
Price said the aeʻo’s resilience comes from its relatively quick breeding cycle and adaptability. The birds reach breeding age in about two years and typically lay four eggs each season, retrying quickly if a nest fails. By contrast, species such as the Newell’s shearwater can take five to six years to reach breeding maturity.
When the ʻio was delisted, federal officials cited stable counts over 30 years, though Price and Peters questioned if data were sufficient. In a sobering counterpoint, nine Hawaiʻi species were removed from the list five years ago after being declared extinct, including eight forest birds and one plant.
“For the waterbirds, it’s straightforward. You’ve got to restore habitat and control the predators.”
Melissa Price, University of Hawaiʻi associate professor
The aeʻo is one of four native waterbirds dependent on wetlands, along with the kōloa maoli, ʻalae keʻokeʻo and ʻalae ʻula. All remain listed under the Endangered Species Act.
Price said targeted habitat restoration and predator control can keep waterbirds on a recovery path. She added that broader success for Hawaiʻi’s imperiled species will require sustained investment and community commitment.
The U.S. Fish and Wildlife Service changed the bird’s status earlier this month, noting gains from roughly 200 birds a century ago to an estimated population near 2,000 in recent years. Overhunting and the loss of coastal wetlands once pushed the species to the brink. Listed as endangered in 1970, the aeʻo benefitted from predator control and the restoration of core wetland habitats across the islands.
The aeʻo will continue to rely on protected wetlands that are not affected by recent federal rule changes, including Hanalei National Wildlife Refuge on Kauaʻi, James Campbell National Wildlife Refuge and the Hāmākua and Kawainui marshes on Oʻahu, and Kanahā Pond State Wildlife Sanctuary on Maui. A recent study led by U.S. Geological Survey researcher Eben Paxton estimated the population averaging as high as 1,932 birds.
