Vultures are scavenging birds of prey that feed mostly on carrion. There are 23 species of vultures, found in warmer regions of Europe, Africa, the Americas, and Asia. Two species have been recorded in the Washington DC metropolitan area: the black vulture and the turkey vulture.
Black Vulture
The black vulture (Coragyps atratus) is a common vulture species found across much of the southern United States. It is a large bird, with a wingspan up to 5 feet, mostly black plumage, and a featherless black head and neck.
Range and Habitat
The black vulture inhabits open country landscapes, often near forests, throughout Central and South America. In North America, its range extends from southern Canada through the southern United States and Mexico. Over the last few decades, it has expanded its range northward.
Black vultures are now common year-round residents in the Washington DC metropolitan area, which is near the northern edge of their range. They can be found throughout the city and in Northern Virginia and suburban Maryland.
Black vultures utilize a variety of habitats in both rural and urban areas, including forests, pastures, swamps, marshes, and suburbs. They roost communally in trees, on buildings, and sometimes on communication towers.
Diet
As scavengers, black vultures eat mostly carrion, preferring fresh carcasses. They have a keen sense of smell to locate carcasses. Their diet includes small animals such as rodents, fish, and eggs. They will also eat plant matter and human garbage when carrion sources are scarce.
In urban areas like Washington DC, black vultures consume roadkill and birds killed by building collisions. They also frequent landfills. Occasionally, black vultures will prey on livestock and pets, usually targeting the young or infirm.
Adaptations
Black vultures have physical and behavioral adaptations that help them thrive as scavengers:
– A bald head and neck – Unlike many other vulture species, the black vulture’s head and neck are featherless. This adaptation likely helps keep them clean when feeding inside carcasses.
– Keen sense of smell – They can detect ethyl mercaptan, a gas produced by the beginnings of decay in dead animals. This helps them find carrion.
– Strong feet and beak – Their talons help them hold onto carcasses while feeding. Their hooked beak can tear tough hides and muscle.
– Communal roosting – Roosting together in large numbers may help them find food sources.
– Vomit defense – When threatened, black vultures vomit semi-digested meat to deter predators.
– Group mobbing – They will swarm together to drive threats away from a carcass.
Turkey Vulture
The turkey vulture (Cathartes aura) is another vulture species found in the Washington DC area year-round. It is slightly smaller than the black vulture, with a wingspan up to 6 feet. The turkey vulture is dark brown to black in color, with a featherless red or orange head.
Range and Habitat
The turkey vulture has a large range across most of North America, Central America, and South America. In the United States, its breeding range extends from southern Canada through the southern states into Mexico.
Turkey vultures occupy open country landscapes across rural and semi-rural areas. They roost communally in trees, on cliffs, and sometimes on man-made structures. Turkey vultures are common throughout the Washington DC area, found even in urban city centers.
Diet
Turkey vultures eat mostly carrion, preferring carcasses freshly killed or slightly decayed. They locate carrion using both keen eyesight and sense of smell. With their excellent flying abilities, turkey vultures can scan wide areas for potential food sources.
The turkey vulture’s diet includes small dead mammals and birds, along with reptiles and amphibians. They consume roadkill and animals killed by collisions with buildings or wind turbines. At landfills, they feed on garbage. Turkey vultures may sometimes kill small, live prey when the opportunity arises.
Adaptations
The turkey vulture has several key adaptations:
– A featherless red head – This likely helps keep bacteria-laden food remains off its plumage when feeding inside carcasses. The red color may also aid in thermoregulation.
– Keen eyesight – Turkey vultures soar high in the air to scan for food using superior eyesight. Their ability to visually spot carrion from aloft complements their keen sense of smell.
– Large wingspan – This allows them to soar and glide efficiently with minimal flapping, perfectly adapted for scavenging over large areas.
– Strong immune system – Their immune system can neutralize anthrax, botulinum toxin, and other harmful bacteria from rotting carcasses.
– Projectile vomiting – Like the black vulture, turkey vultures can regurgitate rancid meat when threatened.
– Communal roosting – Roosting together may aid in locating food.
Ecological Role
As scavengers, both black and turkey vultures provide an important ecosystem service by removing and recycling dead animal remains before they can spread bacteria and disease. By promptly disposing of carrion, vultures help keep the environment clean and healthy.
Throughout their ranges, vultures play a key role as nature’s primary clean-up crew. They prevent the spread of diseases like anthrax by consuming infected carcasses. Vultures have strong stomach acid and immune systems that neutralize viruses and bacteria that can sicken other animals.
Research has shown that the decline or disappearance of vultures from an ecosystem can even have cascading impacts, leading to changes in animal populations and communities. Given their ecological benefits, vultures provide invaluable services to both natural and human landscapes.
Population Status and Threats
Both black and turkey vulture populations remain widespread and generally stable across much of North America. However, vultures face a number of threats including:
– Habitat loss from development
– Collision with vehicles and wind turbines
– Poisoning from lead ammunition in carrion
– Unintended poisoning from vet drugs like diclofenac
– Persecution by ranchers to protect livestock
– Disturbance of nesting sites
More research is needed to fully understand vulture population trends. But available evidence suggests black and turkey vulture numbers are adequate to maintain thriving populations currently across most of their ranges. Their ability to adapt and thrive around human activity contributes to their continued success.
Interactions with Humans
The presence of vultures in urban and suburban environments brings these unique birds into close contact with humans. While some people may find vultures unnerving, most interactions are benign or even beneficial.
Still, their large size and scavenging habits causes unease for some people. And in very rare cases, black vultures may prey on pets. But attacks on live animals are uncommon.
Vultures help control populations of potentially harmful and nuisance species, including rats, skunks, and raccoons by scavenging their carcasses. By cleaning up roadkill and other dead animals, turkey and black vultures provide a free waste management service.
Their congregation in large numbers, loud hisses, and vomiting habits can nuisance issues in some cases. But harassment and lethal control are not legal or effective solutions.
Education programs that teach the ecological benefits of vultures can help the public appreciate these misunderstood birds. Simple avoidance measures like securing trash, using rooftop wire systems, and removing pet food at night can reduce nuisance problems. Learning to co-exist with vultures is key.
Conclusion
In summary, two vulture species – the turkey vulture and black vulture – are year-round residents throughout the Washington DC metropolitan area. As scavengers that feed mostly on carrion, vultures provide valuable ecosystem services by disposing of animal remains. This helps eliminate breeding grounds for harmful bacteria and disease.
Vultures are thriving across their range, but do face some ongoing threats primarily from human activity. Living alongside vultures in our cities requires an appreciation of their important ecologic roles along with some basic coexistence measures to avoid problems. Their unique adaptations make vultures one of the most fascinating and beneficial groups of birds found in our local environments.
