Saving the Endangered Laysan Ducks

Laysan ducks

A team of biologists returned earlier this month from a successful mission to translocate 28 endangered Laysan ducks (Anas laysanesis) within Papahānaumokuākea Marine National Monument.

“This is an important milestone in the survivability of this native duck species, and we thank the Coast Guard, as well as all the project partners, for their critical support of this joint agency wildlife recovery action,” said William Aila Jr., chair of the state Department of Land and Natural Resources.

Wildlife biologists from the DLNR, U.S. Fish and Wildlife Service, U.S. Geological Survey and the Hawai‘i Wildlife Center cared for the wild birds during their capture and transport from Midway Atoll National Wildlife Refuge to Kure Atoll Wildlife Sanctuary aboard the U.S. Coast Guard Cutter Kukui.

In 1911, there were only 11 Laysan ducks recorded in existence. A hundred years later, their population bounced to nearly 1,000 birds, mainly due to conservation efforts. But the Japan-generated tsunami in 2011 wiped out about 40 percent of the ducks’ population.

“The Coast Guard’s coordination with our federal and state partners to relocate and establish a new colony of the critically endangered Laysan duck is an excellent example of our organization’s role as environmental stewards,” said Cdr. Steven Ramassini, Cutter Kukui commanding officer.

After traveling from Washington D.C., Hawai‘i Island, Honolulu and Washington State, the team of translocation specialists arrived at Midway Atoll on a USCG HC-130 Hercules aircraft on Aug. 31. With the assistance of Midway Atoll Refuge staff, the team worked throughout three days and nights to locate and select candidate birds for the half-day sea voyage.

Kure’s “founders” were selected by age class, health and male-to-female sex ratio. The ducks were cared for in aviaries and provided with hydration, nutritional support, health screenings, tasty worms and duck chow to eat, and swimming pools.

“There were also biosecurity measures taken, including a duck foot bath and quarantine of transport boxes and food,” said John Klavitter, National Invasive Species Coordinator for Refuges. “Preventing the movement of invasive species is a major concern when transporting wildlife, people and equipment from one island to another.”

The crew returned from their mission on Sept. 3.

The endangered Laysan duck is the rarest duck in the Northern hemisphere and has the smallest geographic range of any duck species in the world. It once occurred across the Hawaiian Archipelago but disappeared from the main Hawaiian Islands with the arrival of invasive rats around 800 years ago. Its disappearance from the Northwestern Hawaiian Islands occurred later, with the very last population isolated on Laysan Island for more than 150 years.

At the turn of the 20th century, humans introduced rabbits to Laysan Island that rapidly devastated the vegetation, leading to the extinction of three endemic land birds (Laysan rail, Laysan Honeycreeper and Laysan Millerbird).

The Laysan duck population was recorded at 11 birds in 1911; their numbers climbed quickly after the rabbits were eradicated from Laysan in 1923.

In 2004 and 2005, ducks were successfully translocated from Laysan Island to Midway Atoll to increase the species’ chance of survival. Those two populations were approaching 1,000 total birds until the 2011 Tōhoku Tsunami hit their island homes, causing a 40 percent decrease in the population.

Establishing additional populations of the species will reduce its risk of extinction from random disasters, introduced species or disease outbreaks.

“Laysan ducks do not fly between the Atolls, so each additional island reintroduction helps to restore its distribution,” said Michelle Reynolds, Ph.D., of USGS Pacific Island Ecosystems Research Center. “In the face of rising sea levels, a predator-free, larger and higher elevation Hawaiian Island will ultimately be needed to recover the species since inundation is expected to impact wildlife on low-lying islands.”

Kure Atoll is located about 1,350 miles northwest of Honolulu. The 90-hectare atoll was chosen as a reintroduction site because mammalian predators (rats) were eliminated starting in 1993, and the site has been undergoing habitat rehabilitation since 2007. Cynthia Vanderlip and her team from Hawaii’s DLNR Division of Forestry and Wildlife on Kure Atoll have been working diligently to prepare the atoll for the arrival of the ducks and will report sightings of the translocated birds.

This landmark event marks the 10^th Anniversary of the Laysan duck project in 2004, when the first of these island waterfowl were translocated from Laysan Island to Midway Atoll.

Laysan ducks, also known as Laysan teal, are small (15-17 inches in length, 400-500g) with a white eye-ring, patterned brown feathers, and a bright green to purple speculum (the distinctive wing feathers in the secondary flight feathers). Males have a greenish-black bill with bright orange legs and feet. Females are similar but have a paler bill and legs than males. The ducks are mostly nocturnal, insectivorous, and nest in dense cover away from wetlands.