Purple martins are diurnal social birds; they live and breed in colonies but prefer to forage in small groups or in pairs. These birds are agile hunters and eat a variety of winged insects. They primarily feed by hawking, a strategy of catching insects in the air during flight. Rarely, they will come to the ground to eat insects. Purple martins migrate to North America in the spring to breed. Older males typically migrate first and leave the overwintering sites in late December or early January, followed by older females. Younger birds (first yearlings) typically arrive at the breeding grounds up to two months later. When the breeding season is over, Purple martins head south. Some birds leave as early as July and others stay as late as October. Martins generally migrate over land, through Mexico and Central America. When not breeding, martins form large flocks and roost together in great numbers. This behavior begins just prior to the southern migration and continues on the wintering grounds. Purple martins are fairly noisy, chirping, and making sounds that can be described as chortles, rattles, and croaks. The various calls are said to be “throaty and rich” and can be rendered as tchew-wew, pew pew, choo, cher, zweet and zwrack. The males have a gurgling and guttural courtship song, a dawn song, and even a subsong used at the end of the breeding season.