Millerbird

The Millerbird, known scientifically as Acrocephalus familiaris, is a diminutive member of the Old World warbler family, Acrocephalidae. This species is endemic to the Hawaiian Islands, where it has carved out a niche for itself in the island ecosystem.

Identification Tips

When attempting to identify the Millerbird, look for a small warbler that is unique to the Northwestern Hawaiian Islands of Nihoa and Laysan. It is a secretive bird, often preferring the cover of dense, low vegetation. Observers may note that males occasionally sing from more exposed perches.

Habitat

The Millerbird is adapted to life in dense, low vegetation, which provides both shelter and feeding opportunities. This habitat preference makes the bird somewhat elusive, contributing to its secretive reputation among birdwatchers.

Distribution

Historically, the Millerbird was found on Laysan and Nihoa islands. The nominate subspecies on Laysan became extinct in the early 20th century, but the bird has since been reintroduced there. The critically endangered Nihoa subspecies is the only remaining race, confined to the small island of Nihoa in Hawaii.

Behaviour

Millerbirds are known for forming long-term pair bonds and defending their territories for several years. These territories can vary in size, with some reaching up to 2.3 acres, though they are typically between 0.47 and 0.99 acres. The birds' breeding season is influenced by food availability and can occur at various times from January to September.

Song & Calls

The vocalizations of the Millerbird are characterized by harsh chirps and a churring sound. These calls are an integral part of the bird's behavior, particularly during the breeding season when males may be heard more frequently.

Breeding

Breeding in Millerbirds is closely tied to the availability of food and can take place anytime from January to September. The birds are known to maintain long-term pair bonds and defend their breeding territories vigorously.

Similar Species

On its native islands, the Millerbird is unlikely to be confused with any other species. The only other passerines present are finches, which are distinctly different in appearance and behavior.

Conservation Status

The Millerbird is classified as Critically Endangered by the IUCN and Critically Imperiled by NatureServe. Conservation efforts, including the reintroduction of the species to Laysan Island, are ongoing to ensure the survival of this unique Hawaiian avian resident.