The ground tyrants (Muscisaxicola) are a genus of passerine birds belonging to the tyrant flycatcher family Tyrannidae. There are about 13 different species. They are ground-dwelling birds which inhabit open country in South America, particularly the Andes and Patagonia. Several southern species are migratory, moving northward for the winter. Ground tyrants feed on insects and other invertebrates, mainly by picking them from the ground. A flight display is performed during the breeding season. The nest is a cup of twigs or grass which, in most species, is built in a burrow, crevice or under rocks. Ground tyrants are fairly small (13–20 cm in length) with longish legs, a slender bill and an erect posture. The plumage is dull and mainly grey or brown with paler underparts. The head is variably patterned with several species having rufous patches on the crown or white between the bill and eye. The birds have simple calls and are often silent. Systematics and taxonomy A study of mitochondrial DNA by Chesser (2000) has shown that the little ground tyrant (M. fluviatilis) is highly divergent and not closely related to the other ground tyrants. All the remaining species are related and form a monophyletic group, although the spot-billed ground tyrant (M. maculirostris) is somewhat divergent from the others. The little and spot-billed ground tyrants are smaller and browner than the other species and the little ground tyrant also differs in its habitat, occurring near rivers in the Amazon rainforest. The paramo ground tyrant (M. alpinus) and Taczanowski's ground tyrant (M. griseus) were previously treated as a single species but are genetically divergent with the paramo ground tyrant belonging to a southern Andean and Patagonian clade within the genus and Taczanowski's ground tyrant belonging to a central Andean clade. The name plain-capped ground tyrant is used by some authors to refer to M. griseus with paramo ground tyrant used for M. alpinus. The genus name Muscisaxicola is masculine, therefore the species names griseus, cinereus, maclovianus, alpinus and capistratus are correct rather than grisea, cinerea, macloviana, alpina and capistrata. The names flavinucha and albilora are invariable. Species list The genus contains 12 species: Spot-billed ground tyrant, Muscisaxicola maculirostris White-fronted ground tyrant, Muscisaxicola albifrons Ochre-naped ground tyrant, Muscisaxicola flavinucha Paramo ground tyrant, Muscisaxicola alpinus Taczanowski's ground tyrant, Muscisaxicola griseus Cinereous ground tyrant, Muscisaxicola cinereus Rufous-naped ground tyrant, Muscisaxicola rufivertex Dark-faced ground tyrant, Muscisaxicola maclovianus White-browed ground tyrant, Muscisaxicola albilora