Slate-headed Tody-Flycatcher

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.

Compact leaf warbler with two whitish wingbars (one broad and prominent), greenish-gray upperparts, an indistinct crown stripe, and conspicuous white tips to the innermost flight feathers. Bill and legs usually dark. Extremely similar to Yellow-browed Warbler, but grayer and “colder” overall, with less extensive orangish coloration on the lower bill. Also compare with Two-barred Warbler and Greenish Warbler, both of which lack a crown stripe and have more extensive orange on the bill. Breeds in alpine shrubbery in mountain ranges flanking the Tibetan Plateau. Winters mostly in the plains just south of the Himalayas, but also on wet hilltops farther south. Often heard but not seen, it is best told from other leaf warblers by its distinct “chew-wee” call. Song is a remarkable descending insect-like buzz. Prone to long-distance vagrancy.

A small brown-black swallow with a short tail and comparatively weak flight. The forehead, crown, and back of the neck are dull chestnut with faint dark streaks. The back is glossy deep blue with a few narrow whitish streaks; the rump is pale brown and is more prominent in flight. The wings and tail are blackish-brown, and the tail almost square-ended. Underparts are buffy white with blackish-brown streaks, especially the chin, throat, and upper breast. Juvenile is duller and browner than adult, with buff feather edges and faint streaks on underparts. Found mostly as individuals in mixed swallow flocks; different, weaker flight action is characteristic.