The Turkey Vulture: A Cleansing Breeze Of A Bird
And we’re back with another bird-focused installment of Fish, Birds, and Words. You probably thought I’d given this whole writing deal up since I hadn’t published any content since April, didn’t you? This is largely due to the fact that my life has been a tornado of travel for both work and pleasure, and surprisingly enough, it’s hard to write coherently when you’re completely exhausted from such a busy season of life. However much to the chagrin of some of you who thought my career in writing had finished fear not, as just when you thought I was out, I stick my head right back in!
Wait, hang on - that’s not quite the correct Al Pacino (and Sopranos) Godfather 3 line, is it? Did my sleep-deprived brain pull a fast one on me? I seem to have gotten the words mixed up - the real line is “Just when I thought I was out, they pull me back in!”. My sincerest apologies, I really have no idea how I could have butchered that line so poorly.
Anyways In line with my previous writings on this publication, I’ve been compelled to further highlight and convey information on urban wildlife that dwell in close proximity to human communities, yet often aren’t fully understood or appreciated. Without further adieu, the next species I’ve chosen to highlight is one nearly everyone in North America is familiar with, from circling high above the ground with long and dark fixed wings, sitting hauntingly on a tree branch, or even on the side of the highway sticking it’s nearly bald pink head into the fleshy carcass of a recently deceased animal.
That bird, as you may already have guessed, is the all too familiar Cathartes aura, or Turkey Vulture. See, now that butchered Pacino quote earlier makes sense as I simply can’t get the image of the Turkey Vulture’s feeding habits out of my head after learning about their carnal behavior, and now I bet you won’t either.
If Severus Snape Was A Bird: A Brief Introduction
There is perhaps no bird in North America that evokes a larger human sentiment of “ick” than the often maligned Turkey Vulture. Our society damn near unanimously views them as the preeminent dark, mysterious, grim reaper of our landscapes. Their dietary habits, paired with their menacing look, can easily formulate a feeling of fear and dread in our minds and has led us to cast them off as a species best kept to the fringe of our society.
Although their name in latin means a “cathartic breeze”, they rarely evoke that same emotion for most humans who catch a glimpse of them (looking at you, Ted Bundy). Like a dominant baseball closer called upon to finish a tight baseball game and seal the win, the Turkey Vulture often heeds a similar call to finish a near-end ordeal, in the form of eating the remains of a dead or dying animal.
Given the appearance and grim nature of the evolutionary niche that Turkey Vultures have evolved to occupy, society tends to devalue these birds in our communities of the 21st century, and often overlooks their vital role in carrying out healthy ecosystem functions. Like other species that can draw their current-day existence to legislation such as the Migratory Bird Act of 1918 and the Environmental Protection Agency’s 1972 ban on the pesticide DDT, the simple existence of these birds on our landscapes today is another huge conservation win.
Let’s take a moment to learn a thing or two about this incredible bird - with the hopes you come out of this with some new found interest in such a beautiful (I said it), unique, and vital animal to our ecosystem.
The Turkey Vulture: Yes a Vulture, No, Not a Turkey
For starters, perhaps it makes sense to address the obvious question you may have - why is the Turkey Vulture named after the Turkey, and are they a related species? The answer is yes, and also, not really.
Technically Turkey Vultures are related to wild Turkeys insofar in that they’re both species of birds (science officially terms birds as Aves), however within the entirety of the bird world, they’re very distantly related. Turkey Vultures are a part of the order Cathartiformes, or New World Vultures, whereas Turkeys are of the order Galliformes. Cathartiformes are a part of a much larger sub clade of Aves bird species, Neoaves, which comprises roughly 95% of all bird species, while Galliformes are in the rare 5% that fall outside of Neoaves in the clade known as Galloanserae. This group is generally referred to as fowl, and one of the oldest and uniquely evolved avian groups. Isn’t it cathartic to learn of such a fowl history in the bird world? Sorry, I couldn’t resist.
All in all, there’s no definitive account of how exactly the Turkey Vulture got its name, but it’s generally agreed upon that the name derived from some creative human simply likening them to a Turkey given their lack of head feathers. And apparently the name has stuck like roadkill to the highway pavement.
Poor puns aside, the Turkey Vulture is also one of the most widely distributed birds across the Americas. With a total of five subspecies, these birds have a summer breeding range that covers nearly the entire extent of the USA, as well as a year round coverage ranging from Southern California, Texas, Appalachia, Mexico, Central America, all the way to the southern tip of Argentina. With this extensive range, this bird is one of the most ubiquitous on both the northern and southern American landscapes.
With this range, It’s also one of the most easily identifiable birds in North America, with its long black fixed wings reaching over 6ft in length, commonly soaring high in the wind thermals with it’s pink featherless neck. Ah yes, that fleshy head again - lets talk about that unique bit of biology below.
Bald, Beautiful, And An Absolute Marvel of Ecology
There are very, very few species of birds that lack feathers on their head. And really, almost every bird on earth is fully covered in some type of feather, aside from their legs. Feathers themselves are one of the most unique qualities all birds possess, and they serve various functions from enabling birds to fly, thermoregulation their body temperatures, camouflage, and more. So why doesn’t the Turkey Vulture have any feathers on their neck and head? The answer, as I alluded to earlier, is perhaps the main reason as to why many humans believe Turkey Vultures to be the scary death merchants of the bird world.
For the Turkey Vulture, the bald head is an evolutionary trait, honed and adapted over the millennia of their evolution. And why? Because, you guessed it, their diet. Turkey Vultures and other Cathartiformes are what we commonly call scavengers, meaning their main ecological niche is to feed on dead animals, or carrion, in order to kickstart the recycling of these nutrients back into the ecological web.
It’s a grim job, but a vital key in our ecosystems - without scavenger species such as Turkey Vultures, along with smaller mammalian and invertebrates known as detritivores, organic matter would simply pile up in our ecosystems and never break down. That thought evokes quite an imagery to the creative mind, but in reality, this process is one of the most important across all ecosystems and a key cog in our biotic nutrient cycles.
As Cathartiformes such as Turkey Vultures evolved over thousands of years to scavenge on the dead, they lost the need to have feathers on their heads, as it would seemingly only further inhibit their ability to maintain clean feathers amid their bloody feeding escapades.
It’s probably not unsimilar to what Britney Spears found after she shaved her head completely clean in her banner year of 2007, especially after her scavenger-like rampages. Or, similarly, how human men of a certain age begin losing their precious hair, and thus decide to shave their heads completely for both the ease of maintenance and a uniform stylistic approach. Combovers be damned, says your barber. And also the Turkey Vulture.
In fact, this bald headed trait is shared by other birds in what is called the Old World Vulture group, found mostly in Asia and Africa, and who’re quite distantly related genetically to scavenging vultures in the Americas (or New World Vultures). Wait - other vultures halfway across the world from here also share that same bald-headed trait, but aren’t closely related? How is that possible?
Well I assure you, it isn’t due to a fashion trend. This is a product of a concept we call in the bio biz Convergent Evolution. Turns out, amid the millions of years of genetic mutations that provide earth with the vast array of biotic inhabitants, some traits are more helpful than others and are retained throughout generations, regardless of what type of animal you are.
A classic example of convergent evolution is the streamlined body shape that both dolphins and a myriad of fish species possess. You live your life in the water now, eh? Well, it behooves you to be able to swim, and swim well. Over millennia, aquatic-curious mammals began to adapt to their watery environments in the form of evolving fins and torpedo shaped bodies, just like fish, as this appears to be the most advantageous shape to navigate through water. These two groups of animals split from one another over 200 million years ago, proving that if a genetic mutation gives you a leg up in your environment, it just might stick around for thousands and millions of years - regardless of whether one is a reptile, amphibian, fish, or mammal.
Bring Out Your Dead, Bring Out Your Dead: More Mind-Bending Adaptations Of This Bald Beauty
The Turkey Vulture’s bald head isn’t the only marvel of evolution that makes them an incredibly unique bird. As mentioned prior, Turkey Vultures largely utilize wind thermals to take them high in the sky, enabling them to conserve vital energy by using these winds to guide them as opposed to exerting energy by flapping their wings. Other Cathartiformes, as well as many well-known birds of prey also use these wind thermals as a function of energy conservation as well.
But I’ll raise my hand and ask the question you might be wondering. How on earth can a bird see anything from way up that high? Turkey Vultures have been known to drift up to 40,000 feet in the air, which is just about the same height as cruising altitude of a transcontinental airline flight. Although that’s quite rare to document them at that altitude and they’re much commonly seen from lower heights, it still begs the question how on earth can a bird see anything on the ground at tall altitudes, let alone pinpoint a hunk of dead flesh.
Well for one, the Turkey Vulture has an incredible sense of smell, which certainly helps. Various studies have confirmed this, such as a 1938 experiment conducted by Union Oil Company, in which they injected a strong-smelling organic chemical called Mercaptan into various points of their gas lines and then monitored turkey vulture behavior near the pipeline sites. That compound, which smelled of rotting eggs, attracted turkey vultures to those specific sites over others, confirming that their noses often lead them to their delicious morsels. Another study in 2017 found that Turkey Vulture’s olfactory bulbs were substantially larger than their closely related Black Vulture relatives, further confirming their superior smelling abilities.
In addition, a 2013 study in the American Association of Anatomy Journal confirmed that turkey vultures can even detect flesh as small as a few parts per billion in the air, confirming again of their incredible sense of smell reminiscent of Bruce from finding Nemo. In addition to smell, the turkey vulture also has some of the sharpest avian eyesight, with studies confirming they can see carrion from over a mile away (or 5,280 ft above the ground), which enables them to spot even a touch of flesh on the landscape from an incredibly high cruising altitude.
Here’s another putrefying fact that cements the Turkey Vulture’s status as the superstar evolutionary specialist that it is. These birds can puke. And when they do, it’s a lot. And in fact, the way they do it is unique in the bird world, as it were. Bear with me here.
I’m not talking about regurgitation feeding, a common practice among a variety of bird species in which the parents will often throw up partially digested food into the mouths of their willing offspring for sustenance. Oh no. I’m talking about projectile vomit as a function of self defense. Buckle up!
Turkey Vultures are one of the few species of birds that utilize vomit as a defense mechanism, which has been documented to shoot up to 10ft from vulture to unlucky target. Not only is this defense mechanism incredibly unpleasant (to put it lightly), the vomit itself is highly unique. The stomach of the Turkey Vulture contains some of the most acidic stomach acid found in the animal kingdom. This high acidity is another evolutionary trait that enables them to eat carrion with little risk of catching any harmful pathogens. Rabies, Anthrax, Botulism, and Salmonella are just a few of the well known diseases that Turkey Vultures are immune to with this incredible stomach acidity.
And now for the Turkey Vulture’s last, uh, unique trait sharing; they’re also one of the few bird species that utilize a technique called urohidrosis to thermoregulate their body temperature. Only the most scientific term here for literally the act of peeing on their legs to keep cool. Turkey Vultures have been documented doing this, along with other leggy birds such as storks, and the practice may also serve as a way to kill any lingering bacteria stuck to their legs from their prior carnal trompings. They made peeing their pants cool before Billy Madison ever did!
So let’s check the stats here. They’ve got Incredible eyesight. A featherless head for ease of cleaning off blood. Top tier smelling capabilities. Acidic AF stomach acid and a penchant to projectile that substance at anything that startles them. If they’re legs are warm or dirty - they piss on them to stay cool. Wow - I want you to take a moment to appreciate just how specialized (and metal!) this bird truly is.
Heavy Birds and Heavy Metal
On a less humorous note, the history of the Turkey Vulture hasn’t been all smooth sailing in the wind thermals. Yes, these birds have some incredible stomach acid that stops most pathogens in their tracks - but other substances, such as metals and harmful compounds found in pesticides, can cause them serious harm.
Let me provide you with a bit of helpful(?) carnage context. For much of the past three centuries, it’s safe to say Americans have shot a lot of animals across the landscape. And when I say a lot, I mean an astronomical amount that doesn’t even seem real. Take the American Bison as an example; as many as 30 million bison were ranging across North America in 1492 when Columbus made his famous navigational error and hit our continent. Bison and their relic ancestors had been roaming this landscape for hundreds of thousands of years up until that point. Surely with a population of that meteoric proportion, there wouldn’t ever be a risk of their extinction, right? Even with those new pasty humans in their wooden boats?
Wrong, sadly. With the advent of lead shooting rifles in the 16th century, it only took humans in North America about 400 years to bring that bison population from close to 30 million down to roughly 100 in 1902. And really, much of the true bison carnage occurred as human westward expansion sprawled its fingers across the landscape in the mid-19th century, as a full scale assault on the bison was carried out by settlers, market hunters, and poachers. In addition to the steep decline of bison populations, North American settlers in this era also drove the native Carolina Parakeet and Passenger Pigeon to extinction, who’s populations were estimated to number close to a million and 3-5 billion, respectively, in the pre-colonial days. ‘Carnage’ suddenly seems like a weak word to describe that degree of butchery.
On that uplifting note, you might be thinking, jeeze, well that must have been a smorgasbord for scavengers and other detritivores with that much dead flesh on the landscape. Sadly not. Given that so many of these animals were shot with lead bullets, Turkey Vultures, attracted to the kills, would eat flesh and lead bullets alike causing huge buildups of the heavy metals in their bodies, which in turn caused population declines and death.
As humans began to wake up to their impacts on wildlife during the aforementioned carnage of the 19th century, and as many bird species populations were plummeting (including the Turkey Vultures) the Migratory Bird act of 1918 was passed by U.S. congress. In a sweeping win for bird conservation, this law put strict guidelines on bag limits of birds shot, as well as regulation around destroying nests or eggs. This helped reduce lead shot in the environment to a degree, while preserving more bird species populations, particularly waterfowl and other migratory birds. This would begin to set the table for the recovery of the other animals in the food web in the coming decades that rely upon these birds, which benefited the Turkey Vulture.
But it certainly hasn’t been happily ever after for the Turkey Vulture since the Migratory Bird Act. Lead bullets were still used by hunters throughout much of the 20th century and even still today, often causing cases of Turkey Vulture and other scavenger poisonings. Although lead shot has been banned nationally since 1991 for use in waterfowl hunting given it’s risk to wildlife and water quality, it’s still widely used today for big game hunting in North america. A study as recently as 2011 showed that lead poisoning in Turkey Vultures significantly increases during the deer hunting season in California. I, perhaps like you at this point, am struggling to understand how lead hasn’t been banned further given these damning studies of environmental harm.
BRB, Explaining Why DDT Nearly Caused Turkey Vultures To TTYL ASAP
In addition to lead exposure, you simply can’t talk about Turkey Vultures, other scavengers, and birds of prey populations in the 20th century without mentioning good ole DDT. DDT, or Dichlorodiphenyltrichloroethane, was a chemical compound synthesized by Swiss scientists during the WWII-era to combat insect-borne diseases that were causing harm to both civilian and military personnel. The head scientist who synthesized the compound, Dr. Paul Hermann Muller, won a Nobel peace prize in 1948 given DDT’s role in drastically reducing disease such as malaria and typhus spread by insects in war torn communities across europe. This will prove to be ironic in the next few paragraphs, sadly.
As WWII came to a close, chemical companies both domestically and in Europe began to sell DDT to agriculturists in the postwar boom, with data in hand to show that this new chemistry was incredibly effective in killing insect life across the agricultural landscapes. For the next few decades, DDT soon became one of the most widely used pesticides across the North American landscape, with very little governmental regulation of usage and even less thought towards the environmental impacts outside of pest reduction by applicators.
However, the hammer began to fall in the late 1950s and 60s. Many bird species, particularly birds of prey and scavengers like the Turkey Vulture, began to see their populations decline. As a growing concern began in this era as to find the cause, Rachel Carson’s 1962 book Silent Spring catapulted awareness to the general public of pesticide usage, particularly DDT, and it’s negative impact across bird, fish, and other wildlife species. Silent Spring sparked a national public outcry and kicked off what we know today as the environmental movement of the late 60s and 70s, culminating in efforts such as the creation of the Environmental Protection Agency, Earth Day, as well as the U.S. ban on DDT usage in 1972.
So to dig in and answer the question - why was DDT so bad for birds, particularly birds of prey and scavengers? Let’s start from the bottom (of the food chain, that is). Many environmental toxins, such as potent insecticides, can persist in the environment for long periods of time. In addition, these chemistries can also persist in the bodies of animal species across food webs who may inadvertently be exposed through consuming another organism that has that toxin in its body.
Conceptually, this is known as Bioaccumulation, which occurs when trace amounts of these compounds move from lower levels of the food web (i.e. smaller species like insects and small rodents) across and up food webs to more apex species (i.e. eagles, humans, orcas, etc). By the time these compounds reach the top of the food webs, they can be measured in such dangerous levels that they can cause severe health issues and lead to premature death.
In the case of apex predator and scavenger species like the Turkey Vulture, high levels of DDT bioaccumulation led to the thinning of their egg’s shells, as DDT affected the way these birds metabolized calcium, of which egg shells are primarily made out of. This significantly impacted viability of their eggs to hatch, and over several decades caused substantial declines in Turkey Vulture populations, and the near extinction of Bald Eagles, Golden Eagles, Peregrine Falcons, and California Condors. The ban on DDT in 1972 was vital in protecting the above species and countless other animals throughout endemic food webs, and the populations of many of these heavily impacted species has increased steadily in the decades since the ban.
21st Century Turkey Vulture: Sky High Potential
This has been a fun ride, hasn’t it? From projectile defense puking to heavy metal poisoning, the story of the Turkey Vulture’s resilience (and anatomy) is certainly an inspiring one. Particularly in light of the fact that even when humans treat nature in horrendously poor ways, it’s fascinating that certain species with particular adaptations are able to still persist and continue as they have for tens of thousands of years. They’ve really given us the bird with everything humans have thrown at them, I’d say.
So what of the Turkey Vulture now, here in our current-day communities? How is the Turkey Vulture set to fare as we progress further into the 21st century given stressors such as climate change and increased human development? Well as it turns out, they might just be in an optimal position to roll with these changes and continue to thrive as a species.
Since the ban on DDT, Turkey Vulture populations have increased at a steady rate of nearly 2% each year, and now total roughly 28 million birds across their entire range. There’s also evidence to suggest that due to climate change, these birds are beginning to inhabit a larger distribution of habitat both north and south, with some studies indicating a chunk of their current seasonal ranges will eventually become their year round ranges by 2070.
As the human population in the 21st century marches towards the estimated 9 billion mark by 2050, it also begs the question as to what benefit this urban expansion will bring to the Turkey Vulture. Perhaps this growing rate of urbanization and infrastructure development of more roads would benefit a scavenger such as the Turkey Vulture? That evidence is less than clear, it would seem. Although some evidence suggests Turkey Vulture’s roosting sites can be positively altered with road infrastructure in certain communities, there’s also research to confirm that road infrastructure still plays a negative effect on Turkey Vulture populations. Bird Strikes, as it’s called when a vehicle hits a bird on the roadside, are increasing with the onset of human development, and cause a significant threat to Turkey Vulture health and safety.
There may also be some behavioral changes that the Turkey Vulture deploys as it further adapts to a wider distribution across the urban-rural continuum of landscapes. Although not documented yet in Turkey Vultures, it’s closely related North American cousin, the Black Vulture, has recently become behaviorally a more predatory bird in the midwest, killing newborn cattle calves and other smaller domestic wildlife. As a fellow opportunist scavenger, perhaps other similar behavioral adaptations could be in-store for the Turkey Vulture as they expand across a wider range of habitats.
Headed to the Roost - Wrapping Up The Story Of The Turkey Vulture
Poor puns and puking jokes aside, I really hope you’ve enjoyed reading a thing or two about this majestic and unique bird. If anything, I hope learning the story of the Turkey Vulture can help you rethink the value of the less-than-beautiful birds on our landscape, and that regardless of ominous look or grim eating habits, all birds hold a vital role in our ecosystems. I hope you think about that the next time you see one of these birds devouring a chunk of flesh on the roadside, and hope it brightens your day with a hint of calming, beautiful catharsis.