Biology

Active during the day, the turkey vulture is commonly encountered perched, with wings outstretched in the morning sun. The reason for this behaviour is not entirely clear, but it may be to dry out the feathers, prior to taking to the air (3). Once aloft, this species is a graceful flyer, often gliding close to the ground, with wings angled upwards forming a slight V-shape (3) (4). The turkey vulture feeds almost exclusively on carrion and, unlike most birds, has a highly developed sense of smell, which it uses to locate carcasses, even under a cover of vegetation. This ability means that the turkey vulture is often the first scavenger to arrive at a carcass, allowing it to feed before the arrival of larger birds of prey, which drive this species away (2) (5). In response to its diet of rotting meat, the turkey vulture has evolved a remarkably high tolerance for microbial toxins, and plays an important ecological role in disposing of carcasses that could otherwise breed disease (5). Unlike some larger vultures, the turkey vulture very rarely kills, and only tackles sick or injured animals, nestlings and insects (2) (5). The turkey vulture's breeding season varies according to location, with populations in temperate parts of North America laying eggs between May and June, while populations in Central America lay between February and April (2). Breeding in tropical parts of South America is less well known (2), although egg-laying has been recorded between August and January in Chile (5). Turkey vultures do not provide nesting material, and simply lay a clutch of two eggs directly on the ground in shallow caves or under dense undergrowth, or alternatively in a hollow tree stump or log. After 38 to 41 days of incubation, the eggs hatch, and the young are brooded for a further 70 to 80 days before fledging (2). Although turkey vulture populations in Central and South America generally remain in a single location throughout the year, North American subspecies make lengthy migrations. During the period between September and November, loose flocks of tens of thousands of birds form, which fly south to South America, sometimes as far as Paraguay, to spend the winter (2) (5).