The scribble-tailed canastero (Asthenes maculicauda) is a species of bird in the Furnariinae subfamily of the ovenbird family Furnariidae. It is found in Argentina, Bolivia, and Peru.

The scribble-tailed canastero is about 17 cm (6.7 in) long and weighs about 19 g (0.67 oz). It is a large canastero with a unique pattern on its long tail's pointed feathers. The sexes have the same plumage. Adults have a faint pale supercilium and a dark brown stripe behind the eye on an otherwise buffy face. Their forehead is rufous that blends to a blackish brown crown with rufescent buff streaks. Their hindcrown and nape are dark brown with buff streaks and their back and rump are also dark brown but with wider buff streaks. Their wing coverts are dark brown with rufescent edges and their flight feathers dark browish fuscous with rufous-chestnut bases. Their uppertail coverts and central tail feathers have a ragged mix of rufescent to buff-brown, dark brown, and olive-brown streaks. The rest of their tail is mostly dark fuscous with rufescent and olive-brown edges and streaks. Their throat is pale grayish buff, their breast washed with tawny with a band of dark brown streaks on its lower part, and their belly light buff-brownish. Their sides and flanks are streaked dark brown and light buff, and their undertail coverts are light tawny-brown with faint darker streaks. Their iris is brown, their maxilla gray to dark gray, their mandible whitish gray to gray (sometimes with a darker tip), and their legs and feet olive to olive-green. Juveniles have a duller forehead, more mottled underparts, and a less distinct tail pattern than adults.