Maranon Spinetail

The Maranon spinetail is 14 to 16 cm (5.5 to 6.3 in) long and weighs 16 to 17 g (0.56 to 0.60 oz). The sexes have the same plumage. Adults have a dark brownish-gray face and forehead. Their crown and upper back are dark grayish brown that becomes more rufescent brown by the rump and uppertail coverts. Their wings are dark rufous with dark fuscous tips on the flight feathers. Their tail is dark rufous; it is graduated, and the feathers have blunt tips. Their throat is pale grayish, their breast darker brownish gray, their belly a lighter brownish gray, and their flanks gray with an olive tinge. Voice: The Maranon spinetail's song is "a very slow-paced, somewhat nasal 'kieeuuw...keeeu' ", often with several seconds between phrases. It is sung by both sexes.