The Large-headed Flatbill is a small flycatcher that is patchily distributed in lowland South American forests from Colombia and Venezuela south to Argentina. Also known as the Bamboo Flatbill, this flycatcher is strongly tied to bamboo understory in tropical humid forests below 1400 meters in elevation. Small and largely olive, it has a pale yellowish belly and rusty yellow chest, wing covert bars, and flight feather edging with a large, wide bill. This species is smaller and paler than the similar Dusky-tailed Flatbill, which is fairly rare in the western Amazon basin. Large-headed Flatbill can be most easily located in its dense bamboo habitat by its common call, which is a whistled tu-tu.