Raptor factors: Vultures can smell death hundreds of feet up

In American comic books and film, several villains have been called Vulture, the enemy of Spider-Man; ominous, creepy, and associated with death.

I’d like to write that vultures are getting a bad rap, but they are associated with death and are a bit creepy when heads are buried in a carcass.

On the other hand, a well-coifed bald eagle has better sense than to stick his feathered head into muscle and bloody organs. For a turkey vulture with a bald head and a hooked ivory-white beak, not only does it enter the recently deceased, but it earns eyebrow-raising moments with a few other habits.

In hot climates, it can defecate on its own legs. The moisture in the feces evaporates and cools the bird. Ornithologists who banded vultures had to stop out of fear that some of the feces could get trapped in the band and create a health issue for the bird.

There is but one defense against trouble on the ground: projectile vomiting. They can’t get airborne quickly, so the harasser gets a face full of unpleasantness from as far as 10 feet away.

On the positive side, there’s the turkey vulture’s sense of smell. But hold on. Ornithologists have debated since the mid-19th century whether it was the vulture’s sight or ability to smell that led them to the next meal.

One side backed the turkey-vulture-is-a-raptor theory, so of course the eyes had it. Dissent came from those who argued that the nose is the key, and that’s where most opinions landed even though there had not been research that could prove it either way.

Then in 2017, a Smithsonian Institute study was published online in Scientific Reports. The research proved that the nose had it or, specifically, the large olfactory bulb put the turkey vulture’s sense of smell at the head of the class.

Turkey vultures can smell very diluted gases from decomposing bodies from hundreds of feet up. The researcher said that it was not clear which specific chemical was sensed because the smell of death is complex. Others point to a broader source, ethyl mercaptan, which is produced at the start of decay.

Once they zero in on the EAT HERE sign, the vultures use their strong beaks to rip open the container to reach the food. When it comes to foot strength, think chicken not eagle, so stick with the beak.

The turkey vulture is most likely seen over agricultural fields and other open habitat to take advantage of rising columns of air. They have interior defenses against pathogens from the dead animals but none against accumulating contaminants, such as pesticide. Other dangers include electrocution, being shot, and ingesting lead shot from animals that have been shot.

Research has shown that Asian vultures are at risk of lethal kidney failure if they feed from cattle carcasses that have died up to four days after treatment with the anti-inflammatory drug diclofenac.

This is no small problem. In the 1990s, two species of vultures were nearly wiped out in India, later linked to diclofenac. By 2000, without the vultures to eat carrion, the dog population exploded, followed by a surge in rabies. Now the majority of the 30,000 Indians who die from rabies each year were caused by dog bites, and researchers have linked the cause to lack of vultures that kept the landscape clean of carcasses.

Stay with me, because we’re turning to crime scene investigations. Deciding the time of a human death may include the examination of insects that appear a specific span of hours after a person has been killed, body temperature, etc. The absence of flesh, or most of it, changes the equation.

But what if the bones had been scavenged by vultures?

Researcher Lauren Pharr earned a National Science Foundation grant for her research focusing on vulture scavenging at a Texas forensic anthropology research facility, or “body farm,” using human bodies donated for that purpose.

While decomposition and smaller scavengers will take may take days to take the body to bone, a few vultures accelerate decomposition much faster, thus changing the dynamics of time-of-death decisions.

Whether it is the villainous Vulture or the cartoon turkey vulture (Beaky Buzzard) in “Looney Tunes,” our real-life turkey vulture is neither creepy (well, maybe a little) nor simple-minded.

Let’s show it a little respect.

Columnist Sharon Wootton can be reached at 360-468-3964 or songandword@rockisland.com.