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Perception Channels: visual ; tactile ; acoustic ; chemical
The population bottomed at 150 recently in 1993 following a drought in the region. Their present numbers are up to 600, which is considered a success on the part of the US Fish and Wildlife Service. Currently the Laysan Island is now a refuge for these birds, but has been maintained loosely as a Bird Sanctuary since 1909.
US Federal List: endangered
CITES: no special status
IUCN Red List of Threatened Species: critically endangered
Their refuge is an area of high economic value to developers.
The main food staple for this species is macroinvertebrates. The Laysan Duck is not a diver or swimmer and merely dips its head into the water to feed on aquatic plants, seeds and snails. They also do some filter feeding for moth larvae and pupae. A peculiar method of feeding that has been observed in this species is its tendency to run through swarms of adult brine flies with its neck extend and mouth open in order to trap the flies in its mouth. The climate in the Pacific Ocean undergoes little seasonal variation and therefore migration by this duck to follow food is unnecessary, as supplies stay constant year round.
The Laysan Duck originally resided along all of the Hawaiian archipelago but within the past two hundred years has found its range greatly diminished. At the current time the Laysan Duck can only be found on the small, 900-acre, island (Laysan Island) that is under the protection of the US Fish and Wildlife Service.
Biogeographic Regions: oceanic islands (Native ); pacific ocean (Native )
Grouped among the Dabbling ducks such as the Mallard, the Laysan Duck prefers land habitats to aquatic and aerial habitats. The Laysan Duck is normally observed along the coast of Laysan Island or around the inland lake found on the island. This is where they reside year round. Studies of DNA in duck bones throughout the Hawaiian Islands have shown that the Laysan Duck's range once included the entire Hawaiian Archipelago before the mass extinctions that occurred in that region after Polynesian colonization between 400 and 600 AD.
Aquatic Biomes: coastal
Average lifespan
Status: wild: 142 months.
Average weights for this long-lived duck vary with its age. An individual at age 14 can weigh 98.1 grams while an individual at age 45 can weigh 402.0 grams. There is little difference between the plumages of males and females. Both are dull, dark brown with distinctive white eye rings and white feathering on head and neck. The main difference lies with bill coloring: the male bill is yellowish green with black spotting, while the female bill is dull orange. The Laysan Duck has strong wings that allow it quick take offs but not prolonged flight. The Laysan Duck spends most of its time on its legs dabbling into the water and on land for food.
Range mass: 98 to 402 g.
Other Physical Features: endothermic ; bilateral symmetry
Copulation occurs on land during the late fall and winter. Nesting occurs after this with the female building a nest in a well-concealed location. Four eggs are laid usually between April and August but sometimes as early as February and as late as November. The species' overall success has been diminished by human intrusions especially because its reproductive rate is naturally low. Organizations that wish to increase the duck's population size are currently breeding the ducks in captivity.
Average eggs per season: 4.
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
