Tyrant flycatchers range in length from 3 to 16 inches. Old World flycatchers are smaller, ranging in length from 3½ to 9 inches, not including the tail. Flycatchers are usually dark gray, brown, or olive-green, but some are bright blue, red, yellow, or all white or black. Many have a broad, flat bill with bristle-like feathers at the base. The feathers are probably useful for trapping insects. The bill of the tyrant flycatcher may be slightly hooked.
Many tyrant flycatchers have a relatively short squared-off tail, but some have a long forked tail. The scissor-tailed flycatcher (Muscivora forficata), which is the state bird of Oklahoma, derives its popular name from its long forked tail. The tails of Old World flycatchers may be short, long and fanlike, or medium-length with only the middle feathers elongated. One species, the paradise flycatcher (Terpsiphone paradisi), measures 8 inches from the crown to the end of the body but has a 21-inch-long tail.
Many flycatchers perch in exposed places, watching for flying insects, and then dart out to catch the insects on the wing. Other flycatchers hover over the ground or water, pouncing down to catch insects or sometimes small fish. Although Old World flycatchers feed only on insects and spiders, some tyrant flycatchers eat small seeds and berries. The largest tyrant flycatcher, the boatbill (Megarhynchus pitangua), eats birds, mice, small snakes, and frogs. Some tyrant flycatchers are so bold that they scare off much larger hawks and crows.
Although tyrant flycatchers give loud calls, most of them are poor songbirds. In this respect they differ from Old World flycatchers, which sing well. Some tyrant flycatchers build cup-shaped or hanging nests in trees. Most Old World flycatchers make cup-shaped nests in trees or bushes, but some nest in tree boles or mudbanks.
