Description wikipedia

The stripe-crowned spinetail (Cranioleuca pyrrhophia) is a species of bird in the Furnariinae subfamily of the ovenbird family Furnariidae. It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay. The stripe-crowned spinetail is 13 to 16 cm (5.1 to 6.3 in) long and weighs 10 to 16 g (0.35 to 0.56 oz). It is a smallish member of genus Cranioleuca and has unique crown and tail patterns. The species shows considerable plumage variation following Gloger's rule. The sexes have the same plumage. Adults of the nominate subspecies have a wide white supercilium, dark brown lores, dark brown behind the eye, and mixed whitish and brown ear coverts. Their crown is dramatically striped with blackish and buffy brown; the stripes are fainter in southern Brazil and Paraguay. Their hindcrown and back are grayish brown that is browner in southern Bolivia. Their rump and uppertail coverts are browner than the back. Their tail feathers are graduated and very pointed, giving a forked appearance. The central pair of feathers are dark brown or rufous with dark brown inner webs, the next two pairs rufous with dark brown along the shafts and on the tip, and the outer pair rufous. Their wing coverts are rufous, their primary coverts dark brown, and their flight feathers dull brownish. Their throat is whitish, their breast brownish gray or buffish gray, and their belly a darker gray. The breast and belly are paler in southern Bolivia. Their iris is dark red to pale orange to dark brown, their maxilla black to gray, their mandible pinkish horn to pinkish with a dark tip, and their legs and feet olive-green to greenish gray or yellowish brown. Juveniles have an unstriped crown and darker underparts than adults; their underparts are faintly mottled or scaled. Subspecies C. p. striaticeps has more streaking on the crown than the nominate, a slightly browner back, deeper rufous uppertail coverts and central tail feathers, a paler and less gray breast and belly, and a rufescent tinge on the undertail coverts. C. p. rufipennis has crown stripes intermediate between the nominate and striaticeps, an even browner back than striaticeps, and more rufous on some of the flight feathers than the other two subspecies.