Tyrant flycatchers are the Americas' biggest bird family
Tyrannidae packs more than four hundred passerine species from Alaska to Patagonia—the world's largest bird family and the most diverse in the Americas. Most wear camouflage browns and greys, though vermilion flycatchers blaze scarlet. Tiny Myiornis pygmy tyrants are among the family's smallest members.
With 441 species in 104 genera, Tyrannidae is the largest bird family on Earth, and in every American country except the United States and Canada no other bird family is as varied. The name traces to the naturalist Mark Catesby, who in the 1730s called the eastern kingbird "the tyrant"; Linnaeus, an admirer of Catesby, applied it to the whole family. Despite the shared common name, they are not close kin of the Old World flycatchers, and as suboscines they lack the elaborate vocal apparatus of true songbirds.
Sizes vary a great deal. The short-tailed and black-capped pygmy tyrants of Myiornis measure just 6.5–7 cm and weigh 4–5 g, making them the shortest passerines anywhere and giving them the look of a tiny ball. The great shrike-tyrant sits at the other end, 29 cm and about 99 g, while the fork-tailed flycatcher stretches to 41 cm thanks mostly to what are, relative to its size, the longest true tail feathers of any bird.
Most species wear drab browns, greys and whites, and genera such as Elaenia, Myiarchus and Empidonax are so alike that voice is often the only reliable field mark. The vermilion flycatcher and the many-colored rush-tyrant are vivid exceptions. Nearly all eat insects, but the great kiskadee also takes fruit and small frogs. North American species typically sally out from a perch and return, whereas many tropical ones glean from leaves and bark or join mixed flocks.
Diversity piles up in tropical forest: a single lowland evergreen site can hold about ninety species, against single digits in habitats such as palm forest or river edges. Regionally, the Atlantic Forest ranks richest, with the Chocó close behind. Conservation is a worry in the tropics: BirdLife's 2007 assessment put two species found only in Brazil, Kaempfer's tody-tyrant and the Minas Gerais tyrannulet, in the highest threat category, with seven more endangered. Several genera, among them Tityra and Pachyramphus, have since been moved out into their own family, Tityridae.
Source: Tyrant flycatcher
