Near Extinction

Decline to near-extinction

Male Laysan Duck

The decline of the Laysan Duck began 1000-1600 years ago, with the colonization of the Hawaiian Islands by Polynesians and associated non-native mammalian predators.^[3] By 1860, the ducks disappeared from all but Laysan Island (the duck’s namesake), most likely due to predation by introduced rats. Like many isolated island species, the Laysan Duck evolved in an environment lacking mammalian predators, and is ill-suited to defend itself against non-native ground hunters, such as humans, rats, pigs, and Small Asian Mongooses. For example, Laysan Ducks are more likely to freeze their movement rather than flush or fly when startled— a strategy well suited for cryptic defense against Hawaiʻi’s native flying predators, but ineffective against ground predators. Although the non-migratory Laysan Duck can fly, it does not disperse between islands.^[5]

The Laysan Duck found refuge through most of the nineteenth century on rat-free Laysan Island, surviving within the smallest geographic range of any duck species worldwide (415 hectares / 1.60 square miles). Laysan Island gained federal protection in 1909, with the establishment of the Hawaiian Islands National Wildlife Refuge. However, devastation of the island’s vegetation by introduced domestic rabbits brought the duck to the brink of extinction in 1912, with an all-time low population of 7 adults and five juveniles.^[6]

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