Buff-rumped Warbler Myiothlypis fulvicauda

Small ground-dwelling warbler frequently found around water, especially forested streams. Also often seen hopping along trails and sometimes around army ant swarms. Sexes alike; brown above and paler buffy-gray below with pale eyebrow. Frequently flicks tail back and forth so buffy rump and base of tail are very conspicuous. Listen for exceptionally loud song: a series of accelerating chips that increase in volume.