It’s not uncommon for us to be driving along a road in wintertime and find a large group of vultures roosting in a tree. Vultures roost in large community groups, breaking away to forage independently during the day before returning to the same roost in the evening.  They leave before dark to spend the night in the thick canopy of trees. Wintering roosts normally include both turkey and black vultures, often numbering 10, 20, even 65 birds. Surprisingly, they will not segregate themselves by species within these roosts. However, in general, our mountains are more populated by turkey vultures than black vultures.

Whether the turkey vultures we see here in winter are the same as the summer residents remains unknown. Both the turkey vulture and black vulture can be found south of the Mason-Dixon line year-round. But, while the black vulture does not travel north in the summer, the turkey vulture increases its range northward and will breed as far north as southern Canada before migrating back in the fall. So, it’s very probable that, like the robin and other birds, there is a shift in populations, such that our winter birds most likely bred in New York, while our summer stock is wintering in the Carolina Piedmont. A little-known instinct of the Turkey Vulture is its ability to return to its summer feeding grounds on the Vernal Equinox on the same day each year, much as the swallows annually return to Capistrano. Seasonal celebrations are held throughout the country, the most well known held in Hinkley, Ohio.

Turkey vultures are easy to identify in flight. Their wings are lifted upward in a V-shape, or dihedral, over their back. Eagles and hawks have a more flat wingspread. Because they are very light for their size, they tend to teeter back and forth in the wind. These birds can glide for six miles without flapping a wing. The turkey vulture is a very large raptor, whose 6-foot wingspan is a good foot wider than the smaller black vulture.

Unlike the black vulture that hunts by sight the turkey vulture have keen olfactory senses, enabling it to smell it’s carrion from miles away. In fact, it is not uncommon to observe black vultures following the turkey vulture to its food source, and then steal the meal through greater numbers and aggressive tactics. While studies have yet to be undertaken, the combination of the vulture’s olfactory capabilities and the advantage afforded to them by flight makes them likely candidates for use in search and rescue efforts.

Use of turkey vultures in search and rescue would require some minimal level of intelligence, and limited testing suggests they do entertain some trainability. One report tells of a vulture that followed a boy to his bus stop every day. Once the bus was gone, the vulture flew away, but would return each day to met the boy at the bus stop on his return!

Their sense of smell has already landed them an interesting role with gas companies. Once a leak has been identified, a strong-smelling gas is injected into the pipeline. The gas escapes into the air from the leak source, which gathers a large flock of birds. Gas companies then just have to look for these soaring birds to find their leak.

The similarity of the role of the vulture and opossum in ecology are noteworthy. Both feed principally on carrion, can be called ugly, and have disgusting habits. The opossum is known to disgorge a smelling substance from its mouth when scared. Similarly, vultures will regurgitate the contents of their stomach in the direction of their potential predators. I remember the story of a young park ranger who had accidentally caught a turkey vulture in a bear culvert trap. When the ranger opened the door to release the bird, he was quickly introduced to this creatures’ rather gross habit. Whether the vulture does this to intimidate its predator or merely to reduce its weight to enable a quicker getaway is not known, but it appears to be a successful tactic in either case.

Another rather disgusting habit of the turkey vulture is its propensity to discharge urine directly onto its legs.  This serves two very important purposes.  In the summertime, wetting the legs cools the vulture, as the urine evaporates.  (The vulture cannot sweat like us).  In addition, this urine contains strong acids from the vulture's digestive system, which kill any bacteria that may remain on the bird's legs from stepping in its meal.

In this world of roadside gourmets, one must be careful of contracting bacteria, fungi, or infections from well-tendered carrion. It is true that they are offered some protection from disease by the unfeathered bald head, which can enter a carcass and emerge with little parts stuck to its head. But, vultures are known to have a very sophisticated immune system. They can eat diseased and infected carcasses and, yet, there is no trace of bacteria in their droppings. There is even evidence for the claim that the vulture can pass anthrax through its digestive system, killing the virus and remaining unharmed.   How they can do this is unknown, but the answer could be extremely important to medical science.

Turkey Vultures are monogamous, mating for a lifetime that can reach fifty or more years. Normally, one egg is laid with little or no nest being made among the rocky caves or tree hollows. One brood per year is produced.

For years, vultures have been classified as birds of prey along with hawks, owls, and eagles. In 1994, due to recent DNA analysis and other studies on anatomy, physiology, behavior, and cellular biology, vultures have been reclassified and placed in the stork family. There are three species of vultures in North America; the turkey, black and California condor. They all belong to the Cathartidae Family; the American, or New World Vultures. The Old World Vultures have remained within the hawk family Accipitridae. American vultures do not build stick nests, do not have true vocalizations, and do not nest colonially, as do many Old World vultures. However, both have bald heads, feed on decaying carcasses and feed their young by regurgitation. While they both have similar lifestyles, these similarities are now attributed to convergent evolution (unrelated species evolving similar forms/behavior, like birds and bats).