Straneck’s Tyrannulet

Straneck's tyrannulet (Serpophaga griseicapilla), also known as the monte tyrannulet and grey-crowned tyrannulet, is a small species of bird in the family Tyrannidae, the tyrant flycatchers. It is found in Argentina, Bolivia, Brazil, Paraguay, and Uruguay. == Taxonomy and systematics == Straneck's tyrannulet has a confusing taxonomic history. It had been known since the 1990s by the binomial Serpophaga griseiceps, which had previously been assigned to specimens that were later recognized as immatures of what was then the white-bellied tyrannulet (Serpophaga munda) and so was invalid. Roberto Straneck formally described the species and assigned its current binomial in 2007. It was later given its English name in his honor. Straneck's tyrannulet is monotypic. == Description == Straneck's tyrannulet is 9 to 11 cm (3.5 to 4.3 in) long and weighs 4.4 to 7.5 g (0.16 to 0.26 oz). The sexes have the same plumage. Adults have a gray crown and nape with a hidden bit of white on some black central crown feathers. They have a thin white supercilium, a white crescent under the eye, and a dark gray line through the eye on an otherwise grayish white face. Their upperparts are olivaceous brown. Their wings are dusky brownish gray…