BIRD OF THE WEEK: 6/12/2015
SCIENTIFIC NAME: Acrocephalus familiaris
POPULATION: Approx. 565 individuals
IUCN STATUS: Critically Endangered
HABITAT: Dense, shrubby cover near the ground
The Millerbird, a small, Old World warbler, was until fairly recently only found on the rocky, 178-acre island of Nihoa in the Northwestern Hawaiian Islands. Due to this extremely limited range and tiny population, the Millerbird is listed as Endangered under the federal Endangered Species Act.
In a great conservation success story, however, a second population of Millerbirds now resides on the Northwestern Hawaiian Island of Laysan for the first time in nearly a century.
Another subspecies of Millerbird had once occurred on the island of Laysan. But rabbits introduced by Europeans destroyed this island's vegetation and caused the extinction of that bird, as well as two other Laysan birds found nowhere else, by the early 20th century.
Because there was only a single, small population remaining, a goal was set to establish a second, “insurance” population of Millerbirds on Laysan, 650 miles from Nihoa. Rabbits and other destructive mammals were removed from Laysan by 1923.
After intensive habitat restoration by the U.S. Fish and Wildlife Service (FWS), as well as natural regeneration, the island had recovered sufficiently to make it suitable for the Millerbird reintroduction effort.
After years of research and preparation, the first translocation took place in September 2011. In a joint expedition, FWS, ABC, and other partners moved 24 Millerbirds from Nihoa to Laysan, followed by a second translocation of 26 birds the following year.
The new population on Laysan is an unqualified success. Birds are thriving and breeding, with more than 93 chicks successfully fledged so far, and more fledging as time goes on. (Check out one of the final updates by scientists on Laysan who chronicled the Millerbird project.)
The Millerbird isn't the only endangered species benefiting from the conservation efforts on Laysan. The Laysan Finch, Laysan Duck, Hawaiian monk seal, and several plant species are also found there, along with millions of nesting seabirds such as Laysan Albatross and Black-footed Albatross.