Big Black Birds a.k.a. Nature’s Clean-up Detail

Photo by David Powell


In my mind, they are among the first harbingers of spring. Each year, beginning in mid-March, my eyes are drawn skyward daily, searching for their dark form, soaring aimlessly above. I record this event faithfully each year, and my records show that our Turkey Vulture (Cathartes aura) friends return from their wintering grounds around March 15 each year, just in time for Saint Patrick’s Day celebrations. This year it happened on March 17, only not in the cerulean blue open sky, but on KOAT-TV, on the news! They ran a wonderful story, showing one of the first big black birds to return. My first sighting occurred a few days later, on March 21, at 8:30 a.m. in the Rio Grande bosque during a songbird survey. First one large black shape caught my eye, followed by another. Ultimately, ten birds took flight from their night roost in snag along the river bank. I knew that spring was on the way despite the dreadfully windy days of late.

Often unappreciated, vultures perform a vital role in the Earth’s food chain, that of the scavenger. Their scientific name, Cathartes, means purifier. Until very recently, they were considered to be a raptor even though they almost never kill their food, preferring instead to eat carrion. DNA studies conducted within the last ten years have proven that this species is more closely related to the stork family. Unlike other birds of prey, Turkey Vultures have a highly developed sense of smell, and can locate concealed carcasses beneath the forest canopy. Vultures tend to forage alone, but keep a keen watch on the activities of other vultures nearby. A discovered carcass may attract numerous vultures to the site, along with the other, much smaller western scavenger, the Common Raven. Even Golden Eagles are sometimes found at carcasses, and indeed, nearly all species of raptors scavenge when live food is scarce. Vultures, including the Black Vulture which does not occur in New Mexico, are responsible for the removal of tons of animal carcasses in North America each year.

Generally acknowledged as a beneficial scavenger, Turkey Vultures were accorded protection in many states even before the Migratory Bird Treaty Act was passed in 1918. They are; however, still persecuted in some areas and have been trapped, shot, and poisoned by ill-informed humans who fear that they may spread disease among livestock, or kill newborn calves, although direct kills of young are almost certainly due to another avian predator. Over 100,000 vultures were killed in Texas in the mid-1900's by baiting walk in traps with carrion, and the species is also vulnerable to steel leg-hold traps such as the ones that were responsible for the deaths of two gray foxes in Jemez Springs in February 2006.

The population of Turkey Vultures is generally stable in the U.S., particularly as increased education about the benefits of this species has reduced persecution. The greatest causes of mortality for this species today are collisions with automobiles and aircraft, and electrocution on power poles. Collisions with military aircraft are particularly serious, costing the U.S. Air Force 21.6 million dollars, 3 crashed aircraft, and 2 fatalities between 1989-1992. Records of collisions with power lines are rare, and Turkey Vultures often forage directly beneath power lines on carcasses of other less adept species; however, electrocutions occur when the bird perches on power poles, and two body parts, such as wings, or a wing and a foot, touch separate energized portions of the structures, causing electricity to arc between them. Their winspan (63-71 inches), which is smaller only than that of eagles, makes them particularly susceptible to electrocution when the fleshy wrist tissue spans two energized wires.

One of my first and most memorable close encounters with Turkey Vultures happened in the Jemez Mountains. A friend and I were attempting yet again, to find a way to hike to the top of Virgin Mesa without driving around to the west side. We struggled through the increasing steep terrain of the tent rocks, where each step forward was countered by a half slide back. Then, just as we were about to admit defeat, several vultures took flight right over our heads. Their presence was impressive as they wheeled buoyantly on the wind, above and around us oblivious to the limitations of the land-locked humans below. I wondered then, if they nested on the cliffs above us, and they may have been doing just that. They do not build nests, but utilize caves and crevices in cliffs, like the escarpment on Virgin Mesa, and other mesas in the Jemez Mountains. By the time this reaches you, these remarkable black birds should have returned to their mountain home.