never settle voluntarily on the ground, perching instead only on vertical surfaces. Many swifts have long swept-back wings which resemble a crescent or boomerang. One species has been recorded in Maryland. Chimney swift, Chaetura pelagica Hummingbirds Order: ApodiformesFamily: Trochilidae Hummingbirds are small birds capable of hovering in mid-air due to the rapid flapping of their wings. They are the only birds that can fly backwards. Seven species have been recorded in Maryland. Mexican violetear, Colibri thalassinus (R) Ruby-throated hummingbird, Archilochus colubris Black-chinned hummingbird, Archilochus alexandri (R) Anna's hummingbird, Calypte anna (R) Calliope hummingbird, Selasphorus calliope (R) Rufous hummingbird, Selasphorus rufus Allen's hummingbird, Selasphorus sasin (R) Rails, gallinules, and coots Order: GruiformesFamily: Rallidae Rallidae is a large family of small- to medium-sized birds that includes the rails, crakes, coots, and gallinules. The most typical family members occupy dense vegetation in damp environments near lakes, swamps, or rivers. In general they are shy and secretive birds, making them difficult to observe. Most species have strong legs and long toes that are well adapted to soft uneven surfaces. They tend to have short, rounded wings and to be weak fliers. Ten species have been recorded in Maryland. Clapper rail, Rallus crepitans (R*) King rail, Rallus elegans (R*) Virginia rail, Rallus limicola Corn crake, Crex crex (R) Sora, Porzana carolina Common gallinule, Gallinula galeata American coot, Fulica americana Purple gallinule, Porphyrio martinicus (R) Yellow rail, Coturnicops noveboracensis (R) Black rail, Laterallus jamaicensis (R*) Limpkin Order: GruiformesFamily: Aramidae The Limpkin is a large bird in a monotypic family. It is similar in appearance to the rails, but skeletally it is closer to the cranes. It is found in marshes and gets its common name from its appearance of limping as it walks. Limpkin, Aramus guarauna (R) Cranes Order: GruiformesFamily: Gruidae Cranes are large, long-legged, and long-necked birds. Unlike the similar-looking but unrelated herons, cranes fly with necks outstretched, not pulled back. Most have elaborate and noisy courting displays or "dances". One species has been recorded in Maryland. Sandhill crane, Antigone canadensis Stilts and avocets Order: CharadriiformesFamily: Recurvirostridae Recurvirostridae is a family of large wading birds that includes the avocets and stilts. The avocets have long legs and long up-curved bills. The stilts have extremely long legs and long, thin, straight bills. Two species have been recorded in Maryland. Black-necked stilt, Himantopus mexicanus (R*) American avocet, Recurvirostra americana Oystercatchers Order: CharadriiformesFamily: Haematopodidae The oystercatchers are large