Data Zone
Justification of Red List category
Population justification
The population is thought to vary year-to-year in response to rainfall, with periodic fluctuations to below 1,500 mature individuals. The most recent minimum population estimate is 1,815 (1,248– 2,577) individuals, based on a 5-year average (2012–2016) of biannual waterbird census counts (Paxton et al. 2021). Assuming that summer counts reflect the best metric of mature individuals, the population size is here estimated at 1,250-1,750 mature individuals (based on Figure 1 in van Rees et al. [2022]), with Kaua'i, O'ahu and Maui likely supporting 80% of this total.
Trend justification
Populations fluctuate in response to rainfall but the state-wide surveyed number of birds shows a stable or increasing trend overall (Paxton et al. 2021, USFWS 2021, van Rees et al. 2022).
Fulica alai is endemic to the Hawaiian Islands (USA), where it is found on all the main islands except Kaho`olawe (USFWS 2005). Formerly, it was also absent from Lâna`i, which, along with Kaho`olawe, lacked suitable wetland habitat (USFWS 2005). Stragglers reach as far west as Kure in the Northwestern Hawaiian Islands.
It can be expected on virtually any body of water, including estuaries, marshes and golf course wetlands (M. Reed in litt. 2007). It is typically a species of the coastal plain, usually found below 400 m, however some birds inhabit upland pools above 1,500 m on Kaua'i and montane stock ponds up to 2,000 m on Hawai'i (USFWS 2005). Breeding sites are characterised by robust emergent plants interspersed with open, fresh or brackish water, which is usually less than one metre deep. To some extent it is nomadic and irruptive, wandering between islands in response to the availability of water-bodies (Taylor and van Perlo 1998). It may nest in any month of the year (USFWS 2005).
Ongoing threats to this species include predation, degradation of wetlands, and avian disease (USFWS 2021).
Throughout its range, wetlands have been destroyed by drainage for cultivation and developments (Berger 1972, P. Donaldson in litt. 1999, S. L. Pimm in litt. 1999) such as hotels, housing areas, golf courses, shopping centres, landfill sites, military installations, roads and industrial sites (USFWS 2005). Some water-bodies have become overgrown by introduced plants (H. C. Baker and P. E. Baker in litt. 1999, M. Morin in litt. 1999). On O'ahu, artificial wetlands associated with sugarcane plantations have disappeared as these industries have declined on the island (P. Donaldson in litt. 1999). Wetlands continue to be threatened with urban development and invasive plant species, though surveys suggest the population size overall has not been affected detrimentally (Paxton et al. 2021).
Introduced predators include the Black Rat Rattus rattus, Brown Rat Rattus norwegicus, domestic cat Felis catus and dog Canis familiaris, Small Indian Mongoose Herpestes auropunctatus and Cattle Egret Bubulcus ibis (Engilis and Pratt 1993, H. C. Baker and P. E. Baker in litt. 1999, M. Reed in litt. 2007). H. auropunctatus is known to take the eggs, young birds and nesting adults of wetland bird species (USFWS 2005). Predation appears to be a serious problem on golf courses, where F. alai is abundant (M. Reed in litt. 2007).
The species may be poisoned by insecticides and herbicides used to treat water channels on agricultural land and golf courses (Berger 1972, P. Donaldson in litt. 1999), although research is required to confirm this potential threat and its severity. Outbreaks of avian botulism have caused high mortality in several areas (Morin 1996, H. C. Baker and P. E. Baker in litt. 1999, M. Morin in litt. 1999, E. VanderWerf in litt. 2007), a threat that may increase with climate change, increasing urbanisation and invasive aquatic species (USFWS 2021). Changes in precipitation due to climate change, as well as threats of flooding and saltwater intrusion, are thought to be causing degradation of wetland habitat (Timm et al. 2015).
Conservation Actions Underway
Hunting was prohibited in 1939, and the species has been fully protected by US law since 1970. Several key wetland areas have been acquired as refuges or sanctuaries, and other areas are protected by cooperative agreements. Predator control measures and restoration efforts are in place for some wetlands (USFWS 2021). There is partial monitoring of wetland areas and removal of carcasses for botulism outbreaks (USFWS 2021). The species is considered conservation reliant, with cessation of management likely to result in declines (van Rees et al. 2022).
39 cm. Large, aquatic rail. Dark slate-grey plumage, darkest on head. White undertail-coverts, often concealed. Heavy, white bill, somewhat chicken-like, with bulbous frontal shield extending onto crown, variably white, pale yellow, pale blue, or deep blood-red. Red-shield morph also with dark markings near bill tip. Similar spp. American Coot F. americana, a rare visitor, has smaller and dark maroon frontal shield making profile distinctly notched in front. Voice Usually silent, but utters chicken-like keck-keck and keek notes.
Text account compilers
Berryman, A., Vine, J.
Contributors
Baker, H.C., Baker, P.E., Donaldson, P., Lepson, J., Morin, M., Pimm, S.L., Reed, M. & VanderWerf, E.
Recommended citation
BirdLife International (2024) Species factsheet: Hawaiian Coot Fulica alai. Downloaded from
https://datazone.birdlife.org/species/factsheet/hawaiian-coot-fulica-alai on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/11/2024.