The Turkey Vulture (Cathartes aura) is a conspicuous bird of prey often seen soaring over open landscapes across North America. These adaptable scavengers play a crucial role in the ecosystem by consuming carrion. Understanding their habitat, feeding habits, nesting behaviors, and social interactions provides insight into their ecological significance and conservation status.
Habitat and Roosting
Turkey Vultures prefer open areas, including mixed farmland, forests, and rangelands, where they can easily spot carrion. They are frequently observed along roadsides and near landfills, utilizing these human-influenced environments for foraging. At night, they seek secluded high spots for roosting, such as trees, rocks, or other elevated perches. Their preference for open spaces allows for efficient aerial surveillance in their search for food.
Diet and Foraging
The primary food source for Turkey Vultures is carrion, which they locate using a highly developed sense of smell. While they predominantly consume mammals, their diet is opportunistic and can include reptiles, other birds, amphibians, fish, and invertebrates. Turkey Vultures favor freshly deceased animals but will wait for tougher carcasses to soften before attempting to feed. They are adept at targeting the most palatable parts first, even leaving behind scent glands of skunks to avoid their potent odor. Notably, these birds possess robust immune systems, enabling them to consume decaying flesh without succumbing to diseases such as botulism, anthrax, cholera, or salmonella. Unlike their relatives, Black Vultures, Turkey Vultures rarely prey on live animals.
Nesting Habits
Nest Site Selection
Turkey Vultures select nesting sites in a variety of sheltered locations, including rock crevices, caves, ledges, dense thickets, hollow logs, abandoned mammal burrows, fallen trees, and old hawk or heron nests. These sites are often significantly cooler than the surrounding environment, providing a stable temperature for eggs and young. Crucially, they choose locations isolated from human activity and disturbance, emphasizing their need for security during the nesting period. Despite often foraging near human settlements, they prefer to nest in remote areas.
Nest Structure and Longevity
Unlike many bird species, Turkey Vultures do not construct elaborate nests. Instead, they may clear a small area on the ground, remove obstacles, or gather minimal nesting material such as scraps of vegetation or rotting wood. Once a suitable site is established, it may be used repeatedly for over a decade, highlighting the importance of site fidelity and the longevity of their chosen nesting spots.
Nesting Facts
- Clutch Size: Typically 1 to 3 eggs.
- Broods: One brood per year.
- Egg Dimensions: Eggs measure approximately 2.6 to 3.0 inches (6.5 to 7.5 cm) in length and 1.7 to 2.1 inches (4.4 to 5.3 cm) in width.
- Incubation Period: Ranging from 28 to 40 days.
- Nestling Period: Young birds remain in the nest for 60 to 84 days.
- Egg Appearance: The eggs are creamy white with gray, blue, or green tints, marked with spots of purple to brown.
- Hatchling Condition: Newly hatched vultures are covered in down, are often blind, and are defenseless, capable only of emitting a quiet hiss.
Behavior and Flight
The Turkey Vulture’s characteristic slow, teetering flight pattern is believed to aid in soaring at lower altitudes, optimizing their sense of smell for locating carrion. They also soar at higher altitudes on thermals, sometimes forming mixed flocks or “kettles.” On the ground, their movement is less graceful, characterized by ungainly hops, and they are generally less agile than Black Vultures. A common sight, especially in the morning, is Turkey Vultures standing erect with wings spread, a behavior likely related to thermoregulation—warming up, cooling off, or drying their plumage. Outside of the breeding season, they congregate in communal roosts that can number from dozens to hundreds of individuals. During courtship, pairs engage in a “follow flight” display, where one bird leads the other in intricate twisting and turning flights, sometimes accompanied by flapping, which can last for extended periods. Migrating flocks can be impressively large, numbering in the thousands. At a food source, while multiple Turkey Vultures may gather, typically only one feeds at a time, asserting dominance and causing others to wait their turn. Despite their size, they are often displaced by smaller raptors such as Black Vultures, Crested Caracaras, and Zone-tailed Hawks.
Conservation Status
The Turkey Vulture population has shown a positive trend, with an estimated annual increase of approximately 1.8% across North America between 1966 and 2019, according to the North American Breeding Bird Survey. Partners in Flight estimates a global breeding population of 28 million and assigns them a low conservation concern score. Historically, populations were impacted by the pesticide DDT, but they have since rebounded and are now among the most common large carnivorous birds in North America. However, like the California Condor, Turkey Vultures can be vulnerable to poisoning from lead shot found in carcasses or gut piles left by hunters, leading to lead poisoning. Misconceptions that they spread disease have also led to them being trapped or killed, despite their vital role in disease prevention by consuming decaying matter.
Credits
- Kirk, David A., and Michael J. Mossman. (1998). Turkey Vulture (Cathartes aura), version 2.0. In The Birds of North America, edited by P. G. Rodewald. Cornell Lab of Ornithology, Ithaca, New York, USA.
- Lutmerding, J. A., and A. S. Love. (2020). Longevity records of North American birds. Version 2020. Patuxent Wildlife Research Center, Bird Banding Laboratory.
- Partners in Flight. (2020). Avian Conservation Assessment Database, version 2020.
- Sauer, J. R., D. K. Niven, J. E. Hines, D. J. Ziolkowski Jr., K. L. Pardieck, J. E. Fallon, and W. A. Link. (2019). The North American Breeding Bird Survey, Results and Analysis 1966–2019. Version 2.07.2019. USGS Patuxent Wildlife Research Center, Laurel, MD, USA.
- Sibley, D. A. (2014). The Sibley Guide to Birds, second edition. Alfred A. Knopf, New York, NY, USA.
