Physical characteristics

Species in the swallow family are delicately built birds that can fly swiftly with great maneuverability and endurance. Their body length ranges from about 3.9-9.4 in (10-24 cm) and the weight from about 0.4-2.1 oz (10-60 g). The wings are long, pointed, and have nine primary feathers. The tail has 12 feathers and may be deeply forked, somewhat indented, or square-ended. The term "martin" often refers to species with a slightly indented or squared tail. The body plumage is short and pressed close to the skin. The most usual coloration is earth-brown or dark-and-white, often with

Male and female tree swallow (Tachycineta bicolor). (Photo by Windland Rice. Bruce Coleman Inc. Reproduced by permission.)

an attractive green or purple iridescence; rust-brown or rust-red markings are also frequent. The sexes do not differ in external appearance in most species. The flight muscles are strong, and the legs are short and permit only a clumsy waddling gait. The feet are typical of the perching birds. Swallows are primarily insect hunters, catching their prey almost exclusively in flight. To assist in this mode of feeding their small beak has a broad gape, with a wide base that runs almost as far back as the eye.

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