The American Black Vulture, Coragyps atratus, is a large, dark raptor found across the Americas, ranging from the southeastern United States down through Central America to Peru and Uruguay. The Black Vulture plays an important ecological role as a scavenger. While the perception that all vultures feed exclusively on dead matter is widely held, the behavior of the Black Vulture presents a notable exception to this general rule.
The Primary Diet: Scavenging Habits
The Black Vulture’s diet consists overwhelmingly of carrion, including a wide variety of animals from small mammals and reptiles to large livestock. This scavenging lifestyle is supported by a remarkably robust digestive system that provides natural sanitation for the ecosystem.
The birds possess an extremely acidic stomach, with a pH level that can drop as low as 1.0. This harsh chemical environment effectively destroys most disease-causing microorganisms they ingest from decaying meat, including the vegetative form of anthrax. This defense mechanism allows them to safely consume toxic carcasses, preventing the spread of pathogens.
Black Vultures often feed in social groups, sometimes forming large gatherings at a single carcass. Their reliance on sight means they scan the landscape from high altitudes for visual cues of a potential meal. When one bird descends, others quickly follow, leading to group feeding. This group approach allows them to quickly strip a carcass before it becomes too decayed.
Targeting Live Prey: When and Why
While scavenging is the default behavior, Black Vultures are opportunistic and will occasionally attack and consume live animals. These attacks are directed at extremely vulnerable targets that offer little resistance, not random acts of predation. The primary victims are typically newborn or incapacitated livestock, such as calves, lambs, and piglets.
The attacks are often carried out by multiple individuals using coordinated mobbing behavior. They target animals that are still recovering from birth, sick, or otherwise defenseless. The aggressive tactic involves pecking at soft tissues, particularly the eyes, nose, or tongue of the victim. This can cause the young animal to go into shock, leading to its death.
Adult livestock may also be harassed, especially cows that are ill or in the process of giving birth. The Black Vulture’s willingness to engage with live prey is a function of its highly visual foraging strategy. If a visibly vulnerable animal is seen, the vultures may attempt an attack rather than waiting for natural death and decay, which they are unable to detect by smell.
Identifying Black Vulture Behavior
The Black Vulture’s aggressive tendencies are tied to its sensory characteristics when compared to the Turkey Vulture. Unlike the Turkey Vulture, which possesses a highly developed sense of smell capable of detecting the gases of decomposition from a distance, the Black Vulture relies primarily on its keen eyesight. This sensory difference dictates their foraging strategy.
Since they cannot smell a hidden carcass, Black Vultures often soar at higher altitudes, watching for other vultures to descend or looking for visible signs of a meal. They frequently follow Turkey Vultures and, due to their aggressive nature and tendency to feed in groups, they often displace the less aggressive Turkey Vulture from a food source. This social behavior helps compensate for their lack of a strong sense of smell.
Distinguishing the two species in flight is possible by observing a few physical cues. The Black Vulture has a shorter, square-tipped tail and holds its wings relatively flat while soaring. A distinct white patch is visible only on the underside of its wingtips, creating a two-toned appearance. The Turkey Vulture, by contrast, has a longer tail, and its wings exhibit a silvery-gray color along the entire trailing edge.