When it comes to survival, the nine-lived house cat has nothing on the little Laysan duck. Fifteen hundred years ago, it was found on all the main Hawaiian islands, but after the introduction of rats and other predators, only the populations on Laysan and Lisianski islands remained. Following the introduction of rabbits to those islands, and consequent denuding of vegetation, the Lisianski ducks died out and, by 1912, the Laysan population was down to just seven adults and five juveniles.
Since then, the duck has made a slow, slightly unsteady comeback, to the point that its population now hovers around 450. That’s pretty near the estimated carrying capacity of Laysan, whose area of 1,025 acres – just over a square mile – makes it the largest of the Northwestern Hawaiian Islands. But the Laysan duck continues to be vulnerable to extinction. One tsunami could wipe it out. Introduction of a highly contagious disease could be disastrous. Global warming and rising sea levels could destroy the only habitat it now knows.
A draft recovery plan just released by the U.S. Fish and Wildlife Service identifies the duck’s restriction to Laysan as the “greatest current threat” to its survival. Establishing populations of the duck elsewhere is one of the plan’s highest priorities. Up until 1995, the only candidate locations were thought to be in the Northwestern islands. Then subfossil remains of the duck were found on all the main islands, indicating that the bird’s historical range was far more varied than its current habitat. Now the Fish and Wildlife Service is considering re-introducing the Laysan duck not only to other predator-free uninhabited islands, but also to areas on the main islands where predators can be controlled. The sites that are thought to be most likely to support the ducks are Eastern Island at Midway, Nihoa Island, and Kure Atoll in the Northwestern Hawaiian chain, and Kaua‘i and Kaho‘olawe among the Main Hawaiian Islands.
Already, the birds are getting a jump on the restoration actions outlined in the document. A flock of 20 ducks, sharing their own stateroom, motored from Laysan to Midway last fall. There they were released into an environment that the Fish and Wildlife Service, with the help of many volunteers, had labored for 18 months to prepare for the birds’ arrival. Amenities awaiting the ducks included nine freshwa ter seeps and a landscape with abundant bunchgrass for nests.
Michelle Reynolds, who coordinated the relocation, reports that after a short stay in an aviary on Midway, the birds were re leased and all 20 were doing well, as of early December.
— Patricia Tummons
Volume 15, Number 7 January 2005
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