While getting hay for the animals recently, I discovered a very big opossum had died in the barn during the night. I carried the carcass outside the paddock in my manure fork, thinking I would dispose of it later. Next morning, only a few tufts of gray fur remained at the spot where I laid the possum. Meanwhile, a banquet was taking place in the woods beyond.

The neighborhood scavengers had picked up the scent of putrefying possum carcass in the warm May air. During the night, something—possibly a fox—had carried the carcass to a more private spot in the woods behind the barn. By nine o’clock the next morning, several vultures had landed on the roof of the barn. I grabbed the scope and trained it on a handsome turkey vulture.

Craning its neck toward the woods below, it finally raised its wings and dropped down to join the feast now underway.  A black vulture glided in, alighting on the roof about ten feet from where the turkey vulture had been. Training my scope on the corrugated black skin of the vulture’s head, I noticed the bird’s feathers had a soft patina—like ebony keys of an antique piano.
Meanwhile, another black vulture had hopped up on the metal gate connecting the southeast corner of the barn to the back pasture. But this one sported a pair of vivid red tags that made him look like a giant red-winged blackbird. When I finally photographed the tagged individual, it had flown up and settled on the barn roof to rest.

This was evidently one of the tagged vultures I heard about last winter. Somebody in Martinsburg is live-trapping black vultures, equipping them with numbered plastic wing tags, and then releasing them in order to study their travels. Anybody seeing a tagged black vulture is supposed to email the date, location, time, and tag number to vulture.tag@gmail.com. I didn’t see any numbers on this vulture’s tag, and was unable to dig up details about the study before press time.

Bloodhounds of the Bird World

A black and a turkey vulture perched next to each other. Through the scope, the turkey vulture’s red face showed clusters of white bumps below the eye. Compared with the black vulture, the turkey vulture had flaring nostrils, which interconnected in a wide opening above the bill. Did this indicate a superior sense of smell?

In 1826, John James Audubon presented a paper concluding that vultures use sight, not smell, to locate carrion. First, Audubon set a deer skin stuffed with straw in a field. A turkey vulture landed beside it, walked around and then left. Then Audubon hid a rotting hog carcass under a brush pile, yet no vultures came to investigate.

Many scientists, then and now, have questioned Audubon’s conclusion. The olfactory bulb in a turkey vulture’s brain is unusually large and well developed. Yet nobody could present evidence of superior scenting ability until 2012, when scientists scanned the brains of turkey vultures and discovered the olfactory bulb of a turkey vulture averaged twice as many mitral cells than that of 143 other bird species studied. Mitral cells help transmit information about smells to the brain.

Also, the turkey vultures had twice the number of mitral cells as the black vultures, although their brains were one-fifth smaller. There’s now concrete evidence that turkey vultures are the bloodhounds of the bird world, sniffing out carrion so they can clean up the landscape.

While it’s unlikely any vulture smells very good, turkey vultures evidently smell very well!

— Doug is an artist, writer, and naturalist living near Shepherdstown.

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