Rough-legged Tyrannulet Acrochordopus burmeisteri

Small flycatcher found in forest canopy. Confusingly similar to other tyrannulets, but note especially its stubby (not pointy) bill with a very pale base, which can be quite evident since you are often looking straight up at the bird. Voice is another good clue; it often gives sharp whistles, either alone or in a series. It also tends to be more sluggish, perches more vertically, and stays higher up in the trees than other similar tyrannulets. It has two separate populations, one in the Atlantic Forest region, and another along the east slope of the Andes in Argentina, Bolivia, and perhaps far southern Peru. Northward it is replaced by White-fronted Tyrannulet, which is now considered a separate species. The area of overlap is not well known. Rough-legged Tyrannulet is more uniformly colored, showing little or no gray in the crown.