The New Caledonia thicketbird or New Caledonia grassbird (Megalurulus mariei), is a bird species. Previously placed in the "Old World warbler" family Sylviidae, it does not seem to be a close relative of the typical warblers; probably it belongs in the grass warbler family Locustellidae. This species is endemic to New Caledonia. This is a long-tailed, medium-sized "warbler" with a distinctive bold white supercilium. The bird’s plumage is unstreaked, with olive-brown uppersides (including the crown and wings) and creamy white undersides.