Scavenger Angel
~
The Turkey Vulture Reconsidered
First published in the November/December 2007 issue of
Birdwatcher’s Digest magazine
Afternoons at a Virginia hawkwatch in mid-August are not for those without an abundance of patience. With the real migration still several weeks away one can only hope for the early redtail or broadwing to enliven the empty reaches of sky and provide distraction from the infernal heat. Last summer I was atop a local mountain known here in Virginia as a regional hotspot for hawk migration, fully aware that I was too early to expect anything exciting but obstinately hoping anyhow for some kind of accidental miracle (the birder’s perennial disease). Barefoot and in shorts, sweaty binoculars at the ready, I drowsed over some poetry and occasionally scanned the bleak horizon.
Nothing was happening. Absolutely nothing. From over the ridgeline to the northeast, where in a month’s time the broadwings would stream like a shoal of shad, no relieving breeze disturbed the sullen air. Relative humidity stood at a strangling 81%. The only signs of life in this prostrated world were the impassive turkey vultures climbing the thermals, almost imperceptibly rising higher and higher, tilting their dihedral wings this way and that to catch the slightest updraft and then slowly descending to skim the treetops like pelicans over waves. Perfectly realized masters of their aerial element, the great soaring birds seemed capable of defying the gravitational claims of the earth itself.
Big deal. Turkey vultures, or “TVs” as hawkwatchers call them with a kind of impatient condescension, are a dime a dozen. But today these semi-raptors were the only show in town. Setting aside my book I leaned back in the chair to study them more closely. I usually observed them from far below, though occasional dorsal views were obtained from birds flying across the deep valley below me. Favoring the updrafts that make the mountain locally famous, the vultures provided me with abundant opportunities for scrutiny.
To my surprise I found them to be beautiful. Not that I was ever prejudiced against vultures, far from it. As a child growing up in southern Kentucky I announced to my parents early on that my favorite letter of the alphabet was “V” for two beloved creatures: vampires and vultures. My folks took it in stride; a weird enough little kid, but mostly harmless. One summer day we were barreling down the interstate when I spied on the shoulder a bundle of giant dark feathers waving from a pool of dried blood. What was it?
“Probably a buzzard,” my father unwisely began. “Sometimes when they’re eating something by the side of the road a car will come by and …” The remainder of his lesson on automotive ornithology was lost in a din of excited noise spiked with all the pleading I was capable of (which was much). I somehow convinced him to take the next exit, get in the opposite lane, take the following exit and pull over so that I could inspect this wonderful creature at close range. I recall little of my hurried investigation, just a blood-matted carcass and immense gray-black primary feathers lifting and falling forlornly as they caught the blast of semis hurtling past my crouched form.
A common threat to vultures and other scavengers is to be destroyed by traffic when they attempt to feed on previous casualties. I never forgot that incident, and now try to heave carcasses I encounter on country roads off the pavement and into the weeds. And I never forgot my first visit with a turkey vulture. I had often seen them far above, wheeling black motes in the deep blue of space, and to think that the crushed flyblown ruin at my feet could be one and the same thing was a stirring awakening for me, an early intimation of mortality and of the fragility of earthly creatures when placed in the path of our manic industrial civilization. I was a lot more cautious playing around traffic after that.
The vultures were gliding silently by me there on the mountaintop, on occasion angling their skinned heads to give me a passing glance. I noted the gleaming ivory bills and coal-black bodies, the silver linings of flight feathers backing sooty coverts, the thick fingerlike primaries spread wide in the encouraging air. So near was I to their tilting forms that when they rushed overhead I could hear the surf-like rattling whoosh of wind through their pinions. I stood there, alone and slowly melting, for over an hour, becoming acquainted as if for the first time with a mysterious bird that many of us see nearly every day of our lives.
“Let us praise the noble turkey vulture,” said the great American novelist and philosopher Edward Abbey. “No one envies him; he harms nobody; and he contemplates our world from a most serene and noble height.” And yet how many birders can claim to really know him? The turkey vulture is Cathartes aura, from the Greek kathartes, “cleanser, purifier,” and either the Latin aurum, “gold,” or a Latinized South American Indian name, though it seems more likely that this last may have denominated the turkey’s closely related South American relatives, the greater and lesser yellow-headed vultures (Cathartes melambrotus and C. burrovianus, respectively). Early North American settlers referred to the cathartids (New World vultures) as “buzzards,” an appellation which has stuck but correctly refers to the Old World buteos, those large soaring raptors allied with our own red-shouldered and red-tailed hawks.
The turkey vulture is one of three cathartid species currently extant in the United States, the others being the more southerly black vulture and the critically endangered California condor. Mentioned in the late 18th-century chronicles of William Bartram’s expedition to Florida is what was most likely the king vulture, a resplendent Latin American species even the most vulture-leery would describe as beautiful and which formerly ranged at least as far north as the St. John’s River.
While highly similar in physical appearance, New and Old World vultures come from wholly different evolutionary lines; their naked heads and necks are sanitary products of convergent evolution, physiologies shaped by a shared scavenging lifestyle over long eons. Descended from the stork family, from which they derive their vestigial toe-webbing, New World vultures like their wading bird antecedents display feet which are rather weak and unsuitable for running, relegating the birds to a crow-like scuttling hop or slow, ponderous march, while Old World vultures have the stronger and more nimble feet of their hawk ancestors. Our vultures lack a syrinx, the marvelous avian voicebox, and the vulturine repertoire is thus limited to dismal hisses and grunts.
At four to five pounds and with a wingspan of over five and half feet, the turkey is North America’s largest vulture aside from the California condor (a slightly bigger bird: 23 pounds with a nine foot wingspan) but is regularly pushed aside at carcasses by the smaller black vulture, as well as by the Northern caracara (a bald-faced scavenging falcon) and king vulture where their ranges overlap. The black vulture, though slighter shorter and with a wingspan of only 59 inches, actually weighs about a half-pound more than the turkey, and added to that greater bulk is a gluttonous belligerence lacking in their longer-limbed, more timid cousins.
Perched, the turkey vulture’s body and upper wing feathers are charcoal black to deep chocolate brown depending upon the angle of view. The feet, long-toed and clumsy, are incapable of grasping prey in hawk fashion and are instead simply used to secure meat for the ripping bill. The feet and legs are often coated with liquid feces due to the vulture’s habit of urohydrosis, a trait shared with storks which provides a means of cooling naked legs in hot weather as well as killing any bacteria that may have been carried away from the bird’s last supper. (Vultures are necessarily paragons of cleanliness due to the nature of their work; such is the power of their stomach acids that their excreta could even be used as a topical antibiotic, should you ever be in need).
Vultures roost and perch in dead trees not to heighten their morbid reputations but for the plain reason that green branches and leaves hinder the ponderous birds’ take-off and landing. On cool or foggy mornings turkey vultures and condors assume what ornithologists call a “horaltic pose,” standing erect on a tree branch or fence post and facing the rising sun with outstretched wings. It is assumed that this crucifix position simultaneously warms and dries the birds, jumpstarting their metabolisms from the long night while the slow-building heat creates the day’s first updrafts, a necessary atmospheric feature without which a vulture must expend a good deal of wing-flapping energy getting aloft.
The neck is softly ruffed in a black-feathered cowl that can be drawn up in cold weather. The bony head, naked of the elegant contour feathers found on most birds, is the enervating raw red of a peeled skull. But like otherwise objectionable aspects of friends and family, aversion is overcome by repeated exposure; viewed from behind, a drowsing turkey vulture, the few feathers straggling over a wrinkled pate, suggests a balding old man with hypertension nodding over his newspaper.
With its perforated septum and meaty, exposed skin, a turkey vulture’s face cannot be objectively said to demonstrate its most pleasing features, yet even here a delicate beauty may be found by those who truly look. The wonderfully clear brown eyes of the caged vulture, shyly lowered from those of the observer (unlike the brazen stare of the hawk or eagle), are possessed of a warm, quiet dignity. The bill, powerful and curved at the tip like a scrimshaw fishhook, is startling in its immaculate whiteness. A thoughtful visitor to a raptor rehabilitation center, having run the gamut of lordly eagles, brooding buteos and seething accipiters “in durance soundly caged,” will return to the turkey vultures with a new appreciation for their unassuming, solemn serenity.
Like all vultures, C. aura plays a crucial ecological role is removing large and medium-sized carcasses from the environment. Like us, they prefer the flesh of herbivores to that of dogs and other meat-eaters. Able to search a far greater area than their mammalian competitors, vultures are generally the first to find carcasses and thus have their pick of the choicest cuts, leaving the tougher meat, marrow bones and hide—which demand the heavy jaws and teeth that would make flight impossible—to the coyotes and bears, the raccoons and possums.
Strong and able as their bills are, New World vultures lack the tearing strength of their distant Old World relatives, the griffons and white-backs whose formidable bills can skeletonize a stricken impala within minutes. Arthur Cleveland Bent, accomplished bibliographer of avian anecdotes, records in his Life Histories of North American Birds of Prey that “it often happens, owing to the position of the body, or because it is submerged, or because the hide is too tough for the vulture’s beak to tear, that little or none of it is accessible to the birds. Then the vultures gather about the carcass, in large numbers if it is a big one, and wait patiently near at hand until time and decay, making it soft and ripe, shall fit it to their needs. Then they descend and strip it to the bone.”
Like most carnivores turkey vultures have attuned their lives to regular cycles of binge and privation. Should there be a prolonged dearth of carcasses the birds can go many days without feeding, due in part an incredibly efficient soaring method that in ideal conditions allows them to travel over six hours without a single flap. Each primary feather acts as a separate airfoil, maximizing the bird’s ability to trap rising thermals, while relative to body weight turkey vultures have a vast wing area that allows for unparalleled buoyancy. When a large carcass is happened upon the vultures gorge themselves relentlessly, in the nesting season flying crops full of meat back to their eager young.
Not a species overly concerned with keeping up domestic appearances, a turkey vulture “nest” is most likely a cave floor, hollow stump or a precarious cliff-side ledge. The 1-3 large eggs, creamy white and artistically splashed with brown in a kind of Jackson Pollack drip, are laid from early spring through June. While not strictly monogamous as are many birds of prey, turkey vultures are at least capable of long-term relationships, and both parents take turns nesting during the 40-day incubation period and feeding the dark-headed chicks for 80 days thereafter.
Throughout their range in the Western Hemisphere black vultures make a living from watching their red-headed cousins for signs of food; a ring of stately turkey vultures spiraling over a found feast quickly draws a pack of hissing, bill-jabbing Corgyps atratus which immediately take priority at the carcass. Non-confrontational, always patient and forbearing, the turkey vulture simply chooses to wait its turn.
Such is the peaceable aplomb of the turkey vulture that smaller birds, dwarfed alongside the carnivorous vulture, show not the slightest anxiety about being in its proximity. Bent tells us that “small birds have no fear of the buzzards [sic] and vultures flying over, although they quickly took alarm if a hawk appeared. Buzzards often swept over within a hundred feet of doves, meadowlarks and many others without alarming them in the least.” (This passive reputation has been ingeniously exploited by the zone-tailed hawk of the Southwest, which mimics the turkey vulture’s rocking dihedral flight to gain fatal proximity to small birds and rodents.)
I witnessed this ingrained pacifism myself last November. Having deposited the filleted remains of a slain whitetail in a weedy creek bottom I saw within ten minutes the first circling turkey vultures, joined shortly after by their avaricious relations. They all landed a short distance from the carcass in a segregated half-circle: turkey vultures to one side, black vultures on the other. As I watched through binoculars from the ridge above I thought I saw shifty glances passing back and forth such as those that precede a spaghetti Western shootout. Then one of the turkey vultures slowly ambled up to the deer, paused briefly, as if saying grace, and stretched out to feed.
The moment it prepared to take a modest bite the entire venue (the correct term) of black vultures came galloping up to the carcass, wings outstretched to magnify their size, bills agape and neck feathers flared. I could almost hear their meat-crazed hissing. The turkey vulture, resigned but likely not surprised, immediately gave way and retreated a safe distance back to its kin, where they morosely watched the merrymaking like Dickens’ destitute orphans pressing their cold noses against the inn window.
All did not go according to the black vultures’ plan, however; within five minutes first one and then another red-tailed hawk came gliding imperiously down from the ridge and scattered both species of vulture like chaff. The hawks were leisurely eating their fill of the fresh meat and suet from perches atop the carcass, surrounded by twenty-four hungry but respectful vultures, when I withdrew.
Why are turkey vultures, as they unquestionably are, superior at finding food to other vulture species? In 1826 Audubon wrote his first scientific paper on this very question, addressing the tentative belief of some ornithologists that the birds possessed a sense of smell. As birds, like humans, are known to be primarily visual species, Audubon can’t be blamed for thinking they did not; the belief that birds simply couldn’t smell anything persisted until fairly recently. Furthermore Audubon used badly rotten meat in his experiments, assuming that the more rancid the bait the greater likelihood vultures would find it irresistible. But (again like us) vultures prefer their meals freshly killed, and will avoid eating flesh far gone in decay.
It is now understood that many avian species have an olfactory sense, but few are as honed—and important to their owners’ survival—as that of the turkey vulture. In the mid-1980s an experiment was performed in which trace amounts of ethyl mercaptan, the nauseating chemical that arises from decomposing tissue, were introduced into a leaking natural gas pipeline. In minutes turkey vultures were circling an area forty miles away. The leak had been found; the birds were disappointed but the biologists (and the gas company) were elated at a mystery solved.
Turkey vultures are resident from southern Canada to southern South America and the Caribbean. In the fall northern birds migrate to a more southerly clime where carcasses can decompose (and thus be located) throughout the winter. Some birds migrate as far as Central and South American, where their larger size (Bergman’s Rule of zoology dictates that northern species are generally larger than southern ones) allows them to displace local turkey vultures from prime feeding habitats. In the steaming heat of the tropical jungle, their acute sense of smell picks up the odor of decaying meat from beneath the canopy within a single day of an animal’s death. Indeed, non-Cathartes species including the king vulture and Andean condor, lacking this extraordinary facility, depend upon both migratory and resident turkey vultures to find their food in dense Amazonian rainforests and along the Andean foothills.
Gentle, modest and unassuming yet blessed with superlative sensory prowess, elite food finders and matchless riders of the skies’ full arching extent, the turkey vulture is surely a more noble creation than we’ve largely given it credit for. Ours would be a poorer, not to say a filthier and more deadly world without them. If it is true that the meek shall one day inherit the earth, we may all look forward to a planet, or at least a hemisphere, governed by turkey vultures. Given the alternatives, this seems to me a welcome proposition.
Nothing was happening. Absolutely nothing. From over the ridgeline to the northeast, where in a month’s time the broadwings would stream like a shoal of shad, no relieving breeze disturbed the sullen air. Relative humidity stood at a strangling 81%. The only signs of life in this prostrated world were the impassive turkey vultures climbing the thermals, almost imperceptibly rising higher and higher, tilting their dihedral wings this way and that to catch the slightest updraft and then slowly descending to skim the treetops like pelicans over waves. Perfectly realized masters of their aerial element, the great soaring birds seemed capable of defying the gravitational claims of the earth itself.
Big deal. Turkey vultures, or “TVs” as hawkwatchers call them with a kind of impatient condescension, are a dime a dozen. But today these semi-raptors were the only show in town. Setting aside my book I leaned back in the chair to study them more closely. I usually observed them from far below, though occasional dorsal views were obtained from birds flying across the deep valley below me. Favoring the updrafts that make the mountain locally famous, the vultures provided me with abundant opportunities for scrutiny.
To my surprise I found them to be beautiful. Not that I was ever prejudiced against vultures, far from it. As a child growing up in southern Kentucky I announced to my parents early on that my favorite letter of the alphabet was “V” for two beloved creatures: vampires and vultures. My folks took it in stride; a weird enough little kid, but mostly harmless. One summer day we were barreling down the interstate when I spied on the shoulder a bundle of giant dark feathers waving from a pool of dried blood. What was it?
“Probably a buzzard,” my father unwisely began. “Sometimes when they’re eating something by the side of the road a car will come by and …” The remainder of his lesson on automotive ornithology was lost in a din of excited noise spiked with all the pleading I was capable of (which was much). I somehow convinced him to take the next exit, get in the opposite lane, take the following exit and pull over so that I could inspect this wonderful creature at close range. I recall little of my hurried investigation, just a blood-matted carcass and immense gray-black primary feathers lifting and falling forlornly as they caught the blast of semis hurtling past my crouched form.
A common threat to vultures and other scavengers is to be destroyed by traffic when they attempt to feed on previous casualties. I never forgot that incident, and now try to heave carcasses I encounter on country roads off the pavement and into the weeds. And I never forgot my first visit with a turkey vulture. I had often seen them far above, wheeling black motes in the deep blue of space, and to think that the crushed flyblown ruin at my feet could be one and the same thing was a stirring awakening for me, an early intimation of mortality and of the fragility of earthly creatures when placed in the path of our manic industrial civilization. I was a lot more cautious playing around traffic after that.
The vultures were gliding silently by me there on the mountaintop, on occasion angling their skinned heads to give me a passing glance. I noted the gleaming ivory bills and coal-black bodies, the silver linings of flight feathers backing sooty coverts, the thick fingerlike primaries spread wide in the encouraging air. So near was I to their tilting forms that when they rushed overhead I could hear the surf-like rattling whoosh of wind through their pinions. I stood there, alone and slowly melting, for over an hour, becoming acquainted as if for the first time with a mysterious bird that many of us see nearly every day of our lives.
“Let us praise the noble turkey vulture,” said the great American novelist and philosopher Edward Abbey. “No one envies him; he harms nobody; and he contemplates our world from a most serene and noble height.” And yet how many birders can claim to really know him? The turkey vulture is Cathartes aura, from the Greek kathartes, “cleanser, purifier,” and either the Latin aurum, “gold,” or a Latinized South American Indian name, though it seems more likely that this last may have denominated the turkey’s closely related South American relatives, the greater and lesser yellow-headed vultures (Cathartes melambrotus and C. burrovianus, respectively). Early North American settlers referred to the cathartids (New World vultures) as “buzzards,” an appellation which has stuck but correctly refers to the Old World buteos, those large soaring raptors allied with our own red-shouldered and red-tailed hawks.
The turkey vulture is one of three cathartid species currently extant in the United States, the others being the more southerly black vulture and the critically endangered California condor. Mentioned in the late 18th-century chronicles of William Bartram’s expedition to Florida is what was most likely the king vulture, a resplendent Latin American species even the most vulture-leery would describe as beautiful and which formerly ranged at least as far north as the St. John’s River.
While highly similar in physical appearance, New and Old World vultures come from wholly different evolutionary lines; their naked heads and necks are sanitary products of convergent evolution, physiologies shaped by a shared scavenging lifestyle over long eons. Descended from the stork family, from which they derive their vestigial toe-webbing, New World vultures like their wading bird antecedents display feet which are rather weak and unsuitable for running, relegating the birds to a crow-like scuttling hop or slow, ponderous march, while Old World vultures have the stronger and more nimble feet of their hawk ancestors. Our vultures lack a syrinx, the marvelous avian voicebox, and the vulturine repertoire is thus limited to dismal hisses and grunts.
At four to five pounds and with a wingspan of over five and half feet, the turkey is North America’s largest vulture aside from the California condor (a slightly bigger bird: 23 pounds with a nine foot wingspan) but is regularly pushed aside at carcasses by the smaller black vulture, as well as by the Northern caracara (a bald-faced scavenging falcon) and king vulture where their ranges overlap. The black vulture, though slighter shorter and with a wingspan of only 59 inches, actually weighs about a half-pound more than the turkey, and added to that greater bulk is a gluttonous belligerence lacking in their longer-limbed, more timid cousins.
Perched, the turkey vulture’s body and upper wing feathers are charcoal black to deep chocolate brown depending upon the angle of view. The feet, long-toed and clumsy, are incapable of grasping prey in hawk fashion and are instead simply used to secure meat for the ripping bill. The feet and legs are often coated with liquid feces due to the vulture’s habit of urohydrosis, a trait shared with storks which provides a means of cooling naked legs in hot weather as well as killing any bacteria that may have been carried away from the bird’s last supper. (Vultures are necessarily paragons of cleanliness due to the nature of their work; such is the power of their stomach acids that their excreta could even be used as a topical antibiotic, should you ever be in need).
Vultures roost and perch in dead trees not to heighten their morbid reputations but for the plain reason that green branches and leaves hinder the ponderous birds’ take-off and landing. On cool or foggy mornings turkey vultures and condors assume what ornithologists call a “horaltic pose,” standing erect on a tree branch or fence post and facing the rising sun with outstretched wings. It is assumed that this crucifix position simultaneously warms and dries the birds, jumpstarting their metabolisms from the long night while the slow-building heat creates the day’s first updrafts, a necessary atmospheric feature without which a vulture must expend a good deal of wing-flapping energy getting aloft.
The neck is softly ruffed in a black-feathered cowl that can be drawn up in cold weather. The bony head, naked of the elegant contour feathers found on most birds, is the enervating raw red of a peeled skull. But like otherwise objectionable aspects of friends and family, aversion is overcome by repeated exposure; viewed from behind, a drowsing turkey vulture, the few feathers straggling over a wrinkled pate, suggests a balding old man with hypertension nodding over his newspaper.
With its perforated septum and meaty, exposed skin, a turkey vulture’s face cannot be objectively said to demonstrate its most pleasing features, yet even here a delicate beauty may be found by those who truly look. The wonderfully clear brown eyes of the caged vulture, shyly lowered from those of the observer (unlike the brazen stare of the hawk or eagle), are possessed of a warm, quiet dignity. The bill, powerful and curved at the tip like a scrimshaw fishhook, is startling in its immaculate whiteness. A thoughtful visitor to a raptor rehabilitation center, having run the gamut of lordly eagles, brooding buteos and seething accipiters “in durance soundly caged,” will return to the turkey vultures with a new appreciation for their unassuming, solemn serenity.
Like all vultures, C. aura plays a crucial ecological role is removing large and medium-sized carcasses from the environment. Like us, they prefer the flesh of herbivores to that of dogs and other meat-eaters. Able to search a far greater area than their mammalian competitors, vultures are generally the first to find carcasses and thus have their pick of the choicest cuts, leaving the tougher meat, marrow bones and hide—which demand the heavy jaws and teeth that would make flight impossible—to the coyotes and bears, the raccoons and possums.
Strong and able as their bills are, New World vultures lack the tearing strength of their distant Old World relatives, the griffons and white-backs whose formidable bills can skeletonize a stricken impala within minutes. Arthur Cleveland Bent, accomplished bibliographer of avian anecdotes, records in his Life Histories of North American Birds of Prey that “it often happens, owing to the position of the body, or because it is submerged, or because the hide is too tough for the vulture’s beak to tear, that little or none of it is accessible to the birds. Then the vultures gather about the carcass, in large numbers if it is a big one, and wait patiently near at hand until time and decay, making it soft and ripe, shall fit it to their needs. Then they descend and strip it to the bone.”
Like most carnivores turkey vultures have attuned their lives to regular cycles of binge and privation. Should there be a prolonged dearth of carcasses the birds can go many days without feeding, due in part an incredibly efficient soaring method that in ideal conditions allows them to travel over six hours without a single flap. Each primary feather acts as a separate airfoil, maximizing the bird’s ability to trap rising thermals, while relative to body weight turkey vultures have a vast wing area that allows for unparalleled buoyancy. When a large carcass is happened upon the vultures gorge themselves relentlessly, in the nesting season flying crops full of meat back to their eager young.
Not a species overly concerned with keeping up domestic appearances, a turkey vulture “nest” is most likely a cave floor, hollow stump or a precarious cliff-side ledge. The 1-3 large eggs, creamy white and artistically splashed with brown in a kind of Jackson Pollack drip, are laid from early spring through June. While not strictly monogamous as are many birds of prey, turkey vultures are at least capable of long-term relationships, and both parents take turns nesting during the 40-day incubation period and feeding the dark-headed chicks for 80 days thereafter.
Throughout their range in the Western Hemisphere black vultures make a living from watching their red-headed cousins for signs of food; a ring of stately turkey vultures spiraling over a found feast quickly draws a pack of hissing, bill-jabbing Corgyps atratus which immediately take priority at the carcass. Non-confrontational, always patient and forbearing, the turkey vulture simply chooses to wait its turn.
Such is the peaceable aplomb of the turkey vulture that smaller birds, dwarfed alongside the carnivorous vulture, show not the slightest anxiety about being in its proximity. Bent tells us that “small birds have no fear of the buzzards [sic] and vultures flying over, although they quickly took alarm if a hawk appeared. Buzzards often swept over within a hundred feet of doves, meadowlarks and many others without alarming them in the least.” (This passive reputation has been ingeniously exploited by the zone-tailed hawk of the Southwest, which mimics the turkey vulture’s rocking dihedral flight to gain fatal proximity to small birds and rodents.)
I witnessed this ingrained pacifism myself last November. Having deposited the filleted remains of a slain whitetail in a weedy creek bottom I saw within ten minutes the first circling turkey vultures, joined shortly after by their avaricious relations. They all landed a short distance from the carcass in a segregated half-circle: turkey vultures to one side, black vultures on the other. As I watched through binoculars from the ridge above I thought I saw shifty glances passing back and forth such as those that precede a spaghetti Western shootout. Then one of the turkey vultures slowly ambled up to the deer, paused briefly, as if saying grace, and stretched out to feed.
The moment it prepared to take a modest bite the entire venue (the correct term) of black vultures came galloping up to the carcass, wings outstretched to magnify their size, bills agape and neck feathers flared. I could almost hear their meat-crazed hissing. The turkey vulture, resigned but likely not surprised, immediately gave way and retreated a safe distance back to its kin, where they morosely watched the merrymaking like Dickens’ destitute orphans pressing their cold noses against the inn window.
All did not go according to the black vultures’ plan, however; within five minutes first one and then another red-tailed hawk came gliding imperiously down from the ridge and scattered both species of vulture like chaff. The hawks were leisurely eating their fill of the fresh meat and suet from perches atop the carcass, surrounded by twenty-four hungry but respectful vultures, when I withdrew.
Why are turkey vultures, as they unquestionably are, superior at finding food to other vulture species? In 1826 Audubon wrote his first scientific paper on this very question, addressing the tentative belief of some ornithologists that the birds possessed a sense of smell. As birds, like humans, are known to be primarily visual species, Audubon can’t be blamed for thinking they did not; the belief that birds simply couldn’t smell anything persisted until fairly recently. Furthermore Audubon used badly rotten meat in his experiments, assuming that the more rancid the bait the greater likelihood vultures would find it irresistible. But (again like us) vultures prefer their meals freshly killed, and will avoid eating flesh far gone in decay.
It is now understood that many avian species have an olfactory sense, but few are as honed—and important to their owners’ survival—as that of the turkey vulture. In the mid-1980s an experiment was performed in which trace amounts of ethyl mercaptan, the nauseating chemical that arises from decomposing tissue, were introduced into a leaking natural gas pipeline. In minutes turkey vultures were circling an area forty miles away. The leak had been found; the birds were disappointed but the biologists (and the gas company) were elated at a mystery solved.
Turkey vultures are resident from southern Canada to southern South America and the Caribbean. In the fall northern birds migrate to a more southerly clime where carcasses can decompose (and thus be located) throughout the winter. Some birds migrate as far as Central and South American, where their larger size (Bergman’s Rule of zoology dictates that northern species are generally larger than southern ones) allows them to displace local turkey vultures from prime feeding habitats. In the steaming heat of the tropical jungle, their acute sense of smell picks up the odor of decaying meat from beneath the canopy within a single day of an animal’s death. Indeed, non-Cathartes species including the king vulture and Andean condor, lacking this extraordinary facility, depend upon both migratory and resident turkey vultures to find their food in dense Amazonian rainforests and along the Andean foothills.
Gentle, modest and unassuming yet blessed with superlative sensory prowess, elite food finders and matchless riders of the skies’ full arching extent, the turkey vulture is surely a more noble creation than we’ve largely given it credit for. Ours would be a poorer, not to say a filthier and more deadly world without them. If it is true that the meek shall one day inherit the earth, we may all look forward to a planet, or at least a hemisphere, governed by turkey vultures. Given the alternatives, this seems to me a welcome proposition.
