November 15, 2023
One of the birds that is resident here but seems to increase in number during the fall and winter months, is the large and magnificent Turkey Vulture, Cathartes aura. This often-maligned bird is an essential and important member of our food web. Without scavengers, like the Turkey Vulture to clean up dead animals around us, diseases such as botulism, rabies, tuberculosis, distemper, anthrax, and even Black Plague can become major problems.
Turkey Vultures are considered residents to long-distance migrants. We have a population that lives here all year round and does not migrate. In the Fall, northern populations of this species migrate south in large flocks. Many of these birds will keep flying south all the way to Venezuela, Columbia, and Ecuador, and some will stay in Mendocino County until early Spring. As I travel around the valley between the rainstorms, there are large trees with six to ten vultures all sitting around together. It is a good time to observe and learn about the habits of these interesting birds.
The question that often is asked about vultures is how they find their food, usually mammals that are dead. Their main tool for finding dead animals is their olfactory bulb. This smelling organ is the eighth largest of 108 avian species. This was proven in 1938 when Union Oil Company discovered they could find leaks in their gas lines by injecting a bad-smelling organic chemical called mercaptan that mimics the smell of carrion into the gas lines. The vultures would show them where the leaks were by flocking above the smelly area. It is also a way to find a dead animal if you are a farmer like a dead cow. They can also see and use their eyes to help with hunting for dead animals but depend more on their power to smell. If you want to test their eyesight, find a grassy tall hill, and lay down (you can be on a blanket) with your arms straight out. Lay real still and see how long it takes for the vultures to begin flying closely over you. From my own experience, it is thrilling to have such a large bird flying above your body, but I have never had them try anything scary.
Here are a few interesting facts about Turkey Vultures:
They use their urine to clean their legs. They don’t just eat mammals that are dead, they can eat snails, grasshoppers, shrimp, turtles, snakes, chickens, cow manure, and rotten pumpkins. They are opportunistic as most animals are. When they are threatened, they vomit up large amounts of horribly smelly undigested carrion from their stomachs. Even if this vomit does not get on your skin the smell will penetrate your hair and leave a bad taste in your mouth. Think twice before you pick one up, especially about putting it in your car!
Since Turkey Vultures are large birds and have huge wingspans, it takes an enormous amount of energy to fly by flapping their wings. Therefore, finding thermals and gliding is a great way to save energy. Turkey Vultures frequently hold their wings in a V-shape. This specific wing position helps them stabilize themselves if they meet up with turbulent air.
Compared to raptors, vultures are social birds and will roost together in the evenings (sometimes several hundred) and share carrion with eagles, other vultures, ravens, and hawks. Next time you see a Turkey Vulture, take a moment to appreciate the role it plays in keeping our environment clean and to observe their own beauty.