Acrocephalus familiaris
The Millerbird (Acrocephalus familiaris) is a diminutive, highly range-restricted passerine belonging to the Old World warbler family Acrocephalidae. Measuring approximately 13 cm (5.1 in) in length with a slender bill and inconspicuous plumage, it presents a challenge to the casual observer. Its upperparts are a drab olive-brown, contrasting with a dull whitish belly and flanks, often highlighted by a faint, pale supercilium above the eye, which is a key field mark. Weighing merely 10-12 gra...
Found exclusively in dense, low-lying shrublands and tangled dry scrub vegetation on remote, rocky Pacific islands, primarily at low elevations near sea level.
Primarily insectivorous, feeding on a wide variety of small invertebrates such as spiders, caterpillars, moths, beetles, and other arthropods, mostly gleaning them directly from vegetation.
Millerbirds are highly active, diurnal foragers, spending most of their time gleaning insects from the dense foliage and stems of shrubs, often darting in and out of cover. Males are highly territorial, defending their breeding areas vigorously with a loud, complex, and sustained song, often deli...
The Millerbird (Acrocephalus familiaris) is endemic to the remote Northwestern Hawaiian Islands, specifically a highly restricted range within the Papahānaumokuākea Marine National Monument. Historically, the species comprised two subspecies: the Laysan Millerbird (*A. f. familiaris*), which went...
Critically Endangered
- The Laysan Millerbird subspecies (A. f. familiaris) was driven to extinction by introduced rabbits that decimated its island habitat in the early 20th century. - The Nihoa Millerbird (A. f. kingi) once had the smallest known geographic range of any bird species, confined to just one small, rock...