Endangered Species in the Pacific Islands
Laysan Duck / Anas laysanensis
||Laysan ducks are between 15 and 17 inches in length, are brown with a bright green-blue to purple speculum (the distinctive feathers on the secondary wing feathers), and have a white area of feathers around their eyes. The male duck has darker brown face, and the head sometimes is iridescent green. Males have a blue-green bill with black spots along the upper mandible (bill). The female usually has more white around the head and neck, and has a dull brownish yellow bill. Both sexes have orange legs and feet.
|Laysan duck - Photo credit Jimmy Breeden
Habitat & Behavior:
The Laysan duck can only be found on Laysan Island and Midway Atoll NWR in the northwestern Hawaiian islands. These ducks are capable of strong flight but are less likely to fly in escape response than mainland species. Most of these ducks feed at night on a wide variety of terrestrial and wetland vertebrates. The ducks unique brine-fly catching behavior is well known. Before the breeding season (February through August), one can observe ducks running on the mudflats of Laysan to snap flies from the disturbed cloud of insects. Nests are built on the ground under thick vegetation where four to six pale ivory eggs are laid.
Past & Present:
Humans came to Laysan in the 1890s to mine guano, killing 300,000 seabirds in six months and eventually eliminating three endemic landbirds (Laysan rail, Laysan honeycreeper, and the Laysan millerbird). The Laysan duck was hunted for sport and for food. Humans also introduced rabbits that devastated the vegetation, turning the island into a desert-like terrain. The Laysan duck was very close to extinction with the lowest recorded number of 11 in 1911.
In 1993, an alarming population decline on Laysan Island occurred due to drought conditions during El Nino and introduced insects reducing the duck's food source. Numbering about 600 today on Laysan and more than 100 on Midway, they still are at high risk of extinction due to severe weather, disease, accidentental introductions, and habitat degradation.
The Laysan duck was listed as an endangered species in 1967 under the Federal Endangered Species Act. Laysan Island is part of the Hawaiian Islands National Wildlife Refuge created in 1909 and has very restricted public access. The island is also designated as a Research Natural Area where state and federal biologists work closely together to ensure the well being of the island ecosystem. The first Laysan duck Recovery Plan was published in 1982, and a draft revised recovery plan was published in 2004.
The Laysan duck has been successfully bred in various zoos and breeding facilities around the world. Recent fossil and historical data reveal the Laysan duck was once widespread in the Hawaiian Islands (bones have been found on Moloka‘i, O‘ahu, Kaua‘i, Maui, and Hawai‘i), as well as the northwestern Hawaiian islands.
The U.S. Fish and Wildlife Service has successfully controlled alien grass that was overtaking the native bunch grasses used by the ducks for nesting material. Through cooperative research and management efforts with USGS - Biological Resources Division, the Service has learned a great deal about the Laysan duck’s specific habitat needs so that additional populations of this species can be created through reintroduction onto other islands in the Hawaiian Archipelago. In 2004 and 2005, 42 ducks were transferred from Laysan to Midway Atoll. The translocations followed extensive habitat restoration at Midway. This new population has grown rapidly and appears to be healthy. Additional ecosystem repair and habitat restoration will be required before Laysan ducks can be reintroduced elsewhere in their former range.