Bolivian Tyrannulet Zimmerius bolivianus

Small, pale olive-gray flycatcher. Found across a wide elevational range from montane forest all the way up to elfin forest and scrub around the treeline. Perches horizontally, holding its head up; has a pale eye and lacks wingbars. Very pale belly helps distinguish it from the similar Red-billed Tyrannulet, which has a yellow belly and which overlaps with Bolivian at the lower part of Bolivian’s elevational range. Bolivian’s call is a single, descending whistle.