Black Vulture

The Black Vulture seen at Fossil Rim is what we refer to as a "volunteer species." Rather than being placed, they choose to live on our property as they likely have for generations. Guests will likely see several vultures during the duration of their tour.

Appearance

Black vultures are large scavenger birds, with a wingspan that can reach over four feet. Their body is covered in deep black feathers, except for their head and neck, which are bare. This bare skin is gray to black in color and is often rough or bumpy in appearance.  The irises of black vultures are a deep reddish-brown.

Adaptations

Like all of their relatives, black vultures are scavengers, meaning they are specially adapted to eat dead organisms. They play a vital role in their ecosystem, cleaning up messes and preventing the spread of parasites and diseases to other animals. Able to detect the scent of ethyl mercaptan, a gas produced during the decaying process, vultures are likely to show up soon after a death. The incredibly strong gut of the black vulture is able to use a combination of bacteria and acid to break down meat that would be toxic to other animals, providing both a service to their ecosystem and a delicious meal to the bird.  

Because of their ability to protect other species from illness, black vultures are considered a generally healthy pest to have around. They are still labeled a pest by some ranchers because of their occasional tendency to prey on small animals and eggs. They are protected under the Migratory Bird Treaty Act. 

Death and Drafts

In popular culture, vultures are most famous for their tendency to circle above dead or dying animals as they wait for their opportunity to strike. Often, guests at Fossil Rim will notice a few vultures circling and fear they are about to witness an unsavory scene. However, vultures actually spend a lot of time circling not because they've found a meal, but because they've found a warm updraft to coast on, freeing them from having to flap their wings or stay alert on the ground. 

These warm updrafts, known as thermals, are very common in rocky landscapes, as the sun warms rock or even asphalt. Other drafts, called orographic uplifts, are caused by trees, buildings and cliffsides deflecting wind. Black vultures, as well as other circling birds like hawks, love to take advantage of these drafts. Not only do they offer a way to save energy, but they provide a safe means to survey the land below them. If something has died, black vultures are much more likely to be on the ground than in the sky.