The Yellow warbler (Setophaga petechia) is the most extensively yellow of warblers, with golden yellow plumage and rusty streaks on the breast. It breeds in almost the whole of North America and down to northern South America – in summer, the buttery yellow males sing their sweet whistled song from willows, wet thickets, and roadsides across almost all of North America. It is also common throughout the Galapagos Islands, especially found in mangroves or manzanillo trees.It has olive-yellow upper parts and bright yellow underparts with rust-brown streaks on the breast, sides. The wings are dark. The nests of the Yellow Warbler are frequently parasitised by the Brown-headed Cowbird. The warbler often builds a new nest directly on top of the parasitised one, sometimes resulting in nests with up to six tiers.