Birdfinding.info ⇒ After a close brush with extinction the early 1900s, the Laysan Duck fully recovered without direct intervention. Although formerly much more widespread, during its bottleneck the entire global population was confined to Laysan Island. Within its tiny, remote, mid-oceanic range—which also includes Midway and Kure—it is common.
Laysan Duck
Anas laysanensis
Endemic to Hawaii: resident on Laysan, and introduced to Midway and Kure.
Laysan Duck perched on a railing on Sand Island, Midway Atoll. (April 7, 2012.) © Cindy Marple
Formerly more widespread: there is subfossil evidence that it occurred in the main Hawaiian Islands before Polynesian settlement, and a natural population occupied Lisianski in the 1800s.
Between 1911 and 1936, the total population was in the range of 7 to 20 individuals, all on Laysan. It is even thought to have reached the extreme low point of a single female with eggs in 1930. By 1961, however, it had rebounded to about 700.
To address the natural vulnerability of the Laysan population, the U.S. Fish & Wildlife Service developed wetlands on Midway Atoll and in 2004-05 translocated 42 Laysan Ducks there. The Midway population has hovered around 500.
In 2014 a flock of 28 was translocated to Kure, and it has since begun breeding and expanding.
Eventual reintroduction to one or more of the main islands has been discussed in recovery plan documents.
Identification
A small, habitually terrestrial, largely nocturnal, mottled-brown duck with highly variable white spectacles.
On some individuals nearly the entire head is white, while some (possibly just immatures) have only a narrow eyering, but the majority show a broad blotchy eyering or spectacle.
The speculum can be either green or blue.
The male’s bill is typically yellowish, while female’s is more pinkish, and both have variable amounts of dark grayish or brown smudges on the upper mandible.
Laysan Duck, male showing yellow-and-blackish bill; neighbor’s speculum appearing blue. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; December 25, 2008.) © Eric VanderWerf
Laysan Duck. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; December 4, 2019.) © Will Kennerley
Laysan Duck, male showing yellow-and-blackish bill and green speculum. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; December 25, 2008.) © Eric VanderWerf
Laysan Duck with mostly grayish bill. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; January 1, 2020.) © Breck Tyler
Laysan Duck with large, messy white spectacle and yellow-and-blackish bill. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; December 25, 2008.) © Eric VanderWerf
Laysan Duck showing dull-greenish speculum. (Laysan Island, Hawaii; January 25, 2012.) © Cameron Rutt
Laysan Duck showing green speculum. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; October 2, 2019.) © Eric VanderWerf
Laysan Duck with mostly whitish head. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; August 29, 2019.) © Jonathan Plissner
Laysan Duck with mostly white head and unusual white patches in body plumage. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; January 9, 2019.) © Zeke Smith
Laysan Duck with large, messy white spectacle, largely whitish head, and mostly grayish bill. (Eastern Island, Midway Atoll National Wildlife Refuge, Hawaii; April 15, 2009.) © Steve Tucker
Laysan Duck, adult and duckling. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; April 30, 2019.) © Eric VanderWerf
Laysan Duck, apparently three immatures (based on the thin white eyerings) drinking from a puddle. (Laysan Island, Hawaii; July 26, 2014.) © Robby Kohley
Laysan Duck with dark bill, minimal (apparently incomplete) eyering, and green speculum. (Laysan Island, Hawaii; July 26, 2014.) © Robby Kohley
Laysan Duck showing both spectacles. (Laysan Island, Hawaii; March 24, 2010.) © Robby Kohley
Laysan Ducks. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; October 23, 2016.) © Kristina McOmber
Laysan Duck with typical spectacle. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; December 4, 2019.) © Will Kennerley
Laysan Duck with large, irregular white spectacle. (Laysan Island, Hawaii; March 24, 2010.) © Robby Kohley
Laysan Duck, apparently gorging on flies. (Laysan Island, Hawaii; March 23, 2010.) © Robby Kohley
Laysan Ducks, apparently gorging on flies. (Laysan Island, Hawaii; March 24, 2010.) © Robby Kohley
Laysan Duck, duckling learning to catch flies. (Laysan Island, Hawaii; July 25, 2014.) © Robby Kohley
Laysan Ducks, apparently gorging on flies. (Laysan Island, Hawaii; February 2, 2012.) © Cameron Rutt
Laysan Ducks, apparently gorging on flies. (Laysan Island, Hawaii; March 24, 2010.) © Robby Kohley
Laysan Duck, apparently gorging on flies. (Laysan Island, Hawaii; March 25, 2010.) © Robby Kohley
Laysan Ducks. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; February 15, 2017.) © Eric VanderWerf
Laysan Duck. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; August 24, 2017.) © Eric VanderWerf
Laysan Duck, showing white underwings. (Laysan Island, Hawaii; March 23, 2010.) © Robby Kohley
Laysan Ducks in flight, with speculums showing green. (Sand Island, Midway Atoll National Wildlife Refuge, Hawaii; October 2, 2019.) © Eric VanderWerf
Notes
Monotypic species. It has been considered a subspecies of both Mallard and Hawaiian Duck, but this is certainly incorrect as neither of these is even its closest relative (thought to be Pacific Black Duck), and it is not especially similar to either of them.
IUCN Red List Status: Critically Endangered.
References
BirdLife International. 2018. Anas laysanensis. The IUCN Red List of Threatened Species 2018: e.T22680203A130697270. https://dx.doi.org/10.2305/IUCN.UK.2018-2.RLTS.T22680203A130697270.en. (Accessed June 9, 2020.)
eBird. 2020. eBird: An online database of bird distribution and abundance. Cornell Lab of Ornithology, Ithaca, N.Y. http://www.ebird.org. (Accessed June 9, 2020.)
Pratt, H.D., P.L. Bruner, and D.G. Berrett. 1987. A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press.
Pratt, H.D. 1993. Enjoying Birds in Hawaii: A Birdfinding Guide to the Fiftieth State (Second Edition). Mutual Publishing, Honolulu, Hawaii.
Pyle, R.L., and P. Pyle. 2017. The Birds of the Hawaiian Islands: Occurrence, History, Distribution, and Status. Version 2 (January 1, 2017). http://hbs.bishopmuseum.org/birds/rlp-monograph/. B.P. Bishop Museum, Honolulu, Hawaii.