National Wildlife Health Center

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Laysan Duck Translocation


DucksOnLake

LAYSAN DUCK:

The Laysan duck (Anas laysanensis) is a critically endangered duck found on only one spot on earth, the isolated island of Laysan located in the Northwestern Hawaiian Islands National Wildlife Refuge. Laysan Island is fairly small (ca. 6 X 2 km) and is located ~1000 km NW of Honolulu. Laysan is unique among the Northwestern Hawaiian Islands in that it has a large hypersaline shallow lake. Laysan ducks can be found in flocks around the lake and depend on fresh water seeps to raise ducklings. Populations of the Laysan duck fluctuate between 500 and 600 animals. 
Ducks were moved from Laysan Island to Midway (map). NWHI
A picture of ducks on lake

THREATS:

Because of its small size, Laysan island can only support between 500-600 ducks. Because of the duck's restricted range, there was the concern that a catastrophic event on Laysan could wipe them out. Indeed, in 1993, a drought on Laysan in combination with heavy parasite infestations caused a major mortality of ducks. Research by Dr. Michelle Reynolds of the USGS Pacific Islands Ecosystem Research Center (PIERC) indicated that Midway Atoll could provide suitable additional habitat for Laysan ducks. The US Fish and Wildlife Service (USFWS) concurred, and Dr. Reynolds spearheaded plans for translocating ducks from Laysan to Midway.
People

PREPARATION:

The translocation was a collaborative effort between multiple agencies. The USFWS made extensive preparations on Midway Atoll NWR including construction of freshwater seeps, planting of native vegetation, and construction of aviaries into which ducks were to be released. The USFWS also provided the boat transportation from Oahu to Laysan and Laysan to Midway. The USGS-PIESC coordinated the entire translocation effort. The Honolulu Field Station provided veterinary assistance to ensure ducks were medically monitored during captivity and transport.
CaptiveDuck

TRANSLOCATION:

In 2004 and 2005, a total of 42 ducks were captured from Laysan, placed in individual transport crates, and offered food and water. The transit from Laysan to Midway by boat was ca. two days during which time ducks were closely monitored for weight loss, food intake and hydration. Upon arrival to midway, ducks were place in aviaries and observed to ensure they were healthy and eating. Prior to release ducks were fitted with radio transmitters so that they could be monitored to assess survival and reproduction.
DuckRelease

OUTCOME:

The translocation was a success. The founder birds bred successfully and the population quadrupled in three years. A setback did occur beginning in 2008 with avian botulism outbreaks reducing the population 40-50%. The estimated population in 2010 was ~350 birds. Overall, the long term prospects for Laysan ducks on Midway look good and a new translocation is being discussed for another Northwestern Hawaiian island.

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Page Last Modified: Jun 20, 2018