The 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. It is found in woodland and open habitats with scatted bushes and trees in south-central South America, but the details are still unclear. It breeds in Argentina, but may also breed in Bolivia. In addition to these countries, it has been recorded as a non-breeding visitor in Paraguay, and possibly Brazil and Uruguay (it is unclear if it is a regular non-breeding visitor or only an accidental visitor to the last two countries). Visually it closely resembles the white-crested tyrannulet, but its voice is distinctive and its tail shorter. Considerable taxonomic confusion has surrounded this species, which for a period mistak