Large-headed Flatbill

The large-headed flatbill is 12.5 to 13.2 cm (4.9 to 5.2 in) long and weighs 13 to 15 g (0.46 to 0.53 oz). The sexes have the same plumage. Adults of the nominate subspecies R. m. megacephalum have a dark olive crown, dusky lores, a whitish to yellowish streak behind the lores, and a whitish to yellowish eye-ring on an otherwise dark olive face. Their upperparts are dark olive. Their wings are mostly dusky with yellow-olive edges on the flight feathers and ochraceous tips on the coverts; the latter show as two wing bars. Their tail is dusky with yellow-olive edges on the feathers. Voice: The large-headed flatbill's dawn song is "a continuous, rapidly uttered series of tee-tu-twit or whu hu-hoowhip whistles" and its call "a soft mournful wheé-whoo (or "bam-boo") whistle.