Complete Guide To The Black Vulture

Black Vulture Notes

• Black Vultures live throughout North Carolina; they are both widely distributed and abundant.
  • Look for Black Vultures:
    • In forested and semi-open areas, either on high perches or on the ground.
    • In the air, soaring.
• Black Vultures fly at low altitudes, although, in general, they fly higher than their vulture cousins, the Turkey Vultures (Cathartes aura).
  • In a study researching vulture flight behavior, 48% of 3992 Black Vulture in-flight locations were within 100m altitude, compared to 60% of 9622 Turkey Vulture flights (Avery et al. 2011, https://doi.org/10.1002/jwmg.205).
• Food and Feeding
  • Black Vultures are aerial scavengers that feed on any type and size of dead creature, both fresh and well-decayed.
    • Unlike their larger cousin, the Turkey Vulture (Cathartes aura), they cannot smell, so locate their prey by sight.
    • Sometimes Black Vultures scan the ground themselves for carcasses.
      • Food found independently by Black Vultures tends to be large in size and out in the open, like White-tailed Deer (Odocoileus virginianus) or Common Raccoons (Procyon lotor) (Byrne et al. 2019, https://doi.org/10.1002/ecs2.2548).
    • But more often, Black Vultures watch the behavior of other predators or scavengers—most often Turkey Vultures (Cathartes aura)—for signs that they’ve located food, then follow.
      • In a study researching how Black Vultures and Turkey Vultures compete for food, Black Vultures were never recorded at any carcass that was not also visited by at least one Turkey Vulture, and Black Vultures arrived at only four out of 177 carcasses first (Byrne et al. 2019, https://doi.org/10.1002/ecs2.2548).
    • Many Black Vultures will converge on a food source, and they often squabble amongst themselves while feeding.
      • Because they feed in groups, Black Vultures often drive solitary scavengers like Turkey Vultures away from the carcasses.
• Behavior
  • These birds are extremely gregarious; many dozens of individuals may congregate in communal roosts.
    • They perch on any exposed, elevated object, including man-made structures like telecommunications antennas.
    • Black Vultures sun themselves occasionally, although not as often as their cousin species, the Turkey Vulture (Cathartes aura).
      • In study examining how individuals of the two vulture species behave while perched in winter, Black Vultures sunned themselves approximately 9% of the time, compared to Turkey Vultures, who sunned themselves approximately 23% of the time (Byman 2000, https://doi.org/10.1656/1092-6194(2000)007[0297:BOTABV]2.0.CO;2)
      • The vultures turn their bodies either towards or away from the sun and spread their wings so that their bodies can absorb solar radiation.
  • Black Vultures urinate on their legs, a practice called “urohydrosis“.
    • Urohydrosis offers this species two important benefits:
      • First, urinating on their legs helps Black Vultures regulate their body temperatures. Evaporating urine carries excess heat away from the birds.
      • Second, the vultures’ urine contains very strong acids, which helps kill or control potentially harmful microorganisms on their legs.
• Mating and Reproduction
  • Black Vultures don’t build nests in trees. Instead, they nest on the ground, usually hidden by dense vegetation or in hollow logs or caves.
    • This makes the eggs and nestlings vulnerable to terrestrial predators like Rat Snakes (Elaphe obsoleta), Coyotes (Canis latrans).
  • In North Carolina, females usually lay two eggs in April. Both sexes incubate the eggs, which hatch after around 40 days.
  • Both parents feed the nestlings by regurgitating partially digested food.
• Threats
  • As adults, Black Vultures have no predators beyond humans, who shoot, poison, or hit them with cars. Vultures are also electrocuted sometimes by contact with power lines or antennas and towers.