Trilling Tapaculo

The trilling tapaculo is 10.5 cm (4.1 in) long. Males weigh 17.5 to 21 g (0.62 to 0.74 oz) and females 15.4 to 18 g (0.54 to 0.63 oz). Adult males are usually dark gray above and lighter gray below, though sometimes dark gray all over. The flanks and crissum (the area around the cloaca) are dark reddish brown with dusky bars. The female is similar to the male but paler with a dark brown wash. The juvenile is similar to the female with the addition of a scaly appearance due to yellowish edges to feathers. Voice: The trilling tapaculo's song gives it its name. The trill's pace varies geographically, at 21 notes per second in central Peru , 14 in southern Peru , and 20 to 28 in Bolivia . Its scold is similar but shorter and it also has a single-note call .