Vultures | Nature Adventure

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Biology

Vultures, sometimes called condors, are unique birds of prey. In North America, most of our vultures are opportunistic scavengers - birds that are specially adapted to eating dead animals without getting sick. This might make them seem scary or dirty, and a lot of people find the bald heads of turkey vultures (featured in the video above) ugly. Charles Darwin even called them “disgusting”! But, like most things in nature, they actually look like that for a very special reason.

New World vultures typically have a heavy, hunched-over body with shaggy feathers. They are often dull brown or black in color, with white accenting feathers. They’re very big birds, with wingspans averaging around 5- to 6-feet in length - that’s as tall as most adults! - with beaks that are hooked and meant for tearing chunks of softened meat off of bone. As they lack a syrinx (a bird’s vocal chords), they are extremely quiet, only able to hiss or grunt.

Most species of New World vultures lack feathers on their heads, and scientists have been trying to understand why for many years. The old explanation is that this helps keep them healthy and clean, as bacteria from animal carcasses could stick onto their feathers and make them sick. But today, some scientists think that their bald heads might also help keep them cool in hot, dry weather[1]!

Whatever the case may be, our New World vultures have an amazing sense of smell, which helps them find their food. Their noses are extremely sensitive to the chemical ethyl mercaptan, a gas produced by decaying carcasses. If you see vultures flying in circles, they’re likely trying to find the source of that smell somewhere below!

[1]: J. Ward, D. McCafferty, D. Houston, G. Ruxton. (2008) Why do vultures have bald heads? The role of postural adjustment and bare skin areas in thermoregulation. Elsevier. Journal of Thermal Biology. https://doi.org/10.1016/j.jtherbio.2008.01.002

Ecological Importance

Vultures are sometimes considered “nature's garbage disposal”, as they scavenge dead animal carcasses for their food, cleaning up the leftovers from other predators and accidents, like roadkill. Their scientific name, Cathartidae, comes from cathartes, which is Greek for "purifier"!

These birds help maintain a healthy ecosystem by eating these dead animals before they completely decompose. When a body breaks down, it goes through five stages of decomposition: fresh, bloat, decay, advanced decay, and skeletonisation. During the bloating stage, natural bacteria in the body’s stomach begin to break down the insides of an animal; this produces gas, which vultures can sense and use to find their meal.

During the later parts of the decomposition process, large amounts of nitrogen, phosphorus, magnesium, potassium and calcium are released into the soil. This can be great for plants, since this is basically a fertilizer, but too much of it at once can actually hurt them! Additionally, insects like blowflies and other animals, like foxes and skunks, may also be attracted to the smell of decay. These creatures have the potential to spread diseases like dysentery or rabies - so it's important to get rid of the body quickly!

Vultures have extremely acidic stomachs to help them digest old, rotting meat. In fact, this acid is so strong that it can even digest metal! This keeps them safe by breaking down any bacteria inside or on the surface of the carcass, including those that cause botulism, anthrax, hepatitis, and more. When vultures are removed from the environment, cases of people and animals getting sick go way up! This is because there's nothing around to take those pathogens - bacteria and viruses that make us sick - and deactivate them before they can spread.

With vultures cleaning up the environment, plants can get just the right amount of nutrients to thrive, and the people and wildlife who live nearby all stay healthy!

Did you know?

Of all the birds in North America, vultures have possibly the worst reputation. People find them scary, ugly, and associate them with death. This leads to people sometimes shooting them out of fear! Worse, vultures are susceptible to lead poisoning and other heavy metals from the bullets some hunters use on their prey. Even though vultures can dissolve metals, this becomes a poison that builds up in their bones over time.

Because vultures also help clean up roadkill, this means that they're more likely to be hit by cars. Many of the vultures in zoos and rehabilitation centers today were injured by car accidents, barbed wire fences, gunshots, or poisoning. Usually these birds can never be released into the wild again, because many of them loose their ability to fly!

But vultures can live a long time in captivity. In the wild, they might live around 20 years; but when they're taken care of by professionals, they can live to be over 45 years old! Vultures are also gentle birds, and they can form close bonds with their caretakers. Some vultures go on to be ambassador animals, which are taken on shows to teach people about the importance of wildlife!

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