This interest in animals eventually took him to the California Academy of Sciences, where he did research on sharks, birds, and manatees. He also established a turkey vulture colony on the roof of the museum and began delving in to the mysteries of these strange birds.
Long and I found a table on the roof deck of the brewery. I bought him craft beer and peppered him with questions. To start off, I wanted to know why turkey vultures stay up in the air for all those hours on end.
“Well, right, that’s one question,” he said. “Presumably they spend all that time in the air because it’s hard to find food; they have to move around a lot to locate dead animals. But that raises all sorts of other questions.” How do they eat carcasses without getting sick? How does their extreme mobility affect their lives? Do they return to regular homes? And how do they manage this life suspended in midair when they have to molt and replace their feathers? One of the most stubbornly bewildering mysteries about turkey vultures, he said, has to do with their strange proclivity for pooping on their legs. Several common theories attempt to explain this, but none stands up to scrutiny. “You’ll see these ‘fun facts’ about turkey vultures on the Web,” Long said, “and they’ll often say turkey vultures defecate on their legs to cool off. Well, in this colony we had in San Francisco, they were doing that in the coldest part of winter.” So that doesn’t make any sense. This awkward mystery concerning a sometimes-awkward bird, I figured, was a good place to start.
Intestinal Fortitude
Here’s a slightly better explanation for the leg pooping: It armors the vultures by covering their feet with good germs that fight off the pathogens swarming in their food. This is plausible: Turkey vultures are always coming into contact with virulent microbes, and they have other, similarly bizarre means of protecting themselves.
It’s not that turkey vultures like rotten meat, Long said. When he gave the birds in his colony a choice, their preferences were always clear. “We did simple experiments,” he said. “Here’s meat from a dead sea lion that’s been on the beach for a week, and here’s fresh meat that we just got in Chinatown. They went for the fresh stuff, always.”
But they generally eat rotten meat, because that’s what they can find. Turkey vultures use their noses to detect the chemicals produced by decomposition, then zero in on the source. This capability is unusual—most birds have a weak sense of smell, or none at all. You sometimes hear that you aren’t supposed to touch a baby bird because the mother will reject it if it smells wrong: “It’s a myth,” Long said. “The mother would never notice the difference.” Turkey vultures, on the other hand, are equipped with olfactory organs that can pick out a few molecules of decay, even diluted in the wash of high-altitude wind. When a turkey vulture detects the scent of rot, it circles down, tracing the plume of chemicals to its source. They are so good at zeroing in on dead things that other animals use them as guides. California condors, for instance, don’t have such a great sense of smell, so they follow turkey vultures and then bully the smaller birds away from the prize. Humans also watch turkey vultures: In Florida, a Dade County Sheriff’s officer told Long that he will always check when he sees the birds circling, because you never know—it could just be a dead alligator, or it could be a human body.
Once a turkey vulture finally lands beside its festering quarry, it faces a more formidable challenge: It has to actually eat the thing. Sometimes it’s a healthy animal that a car dispatched, but other times it’s an animal that died from disease. The vultures have no way of differentiating between diseased and healthy as they gulp down the raw meat and organs. But turkey vultures have incredibly powerful stomach acids that seem to wipe out anything they touch. “This has been the subject of a lot of curiosity, but very little medical research,” Long told me. “They will eat something with a very high E. coli or Listeria load and they will be fine. They can eat stuff that’s tested positive for rabies, Hantavirus, cholera; when it comes out the other end, there’s just no trace. They are virtually indestructible.”
In the 1930s, after an outbreak of hog cholera in livestock, the USDA worried that turkey vultures were spreading germs and advised farmers to shoot them. As we now know, the birds were actually doing the opposite: disinfecting tainted meat in the crucibles of their stomachs.
Still, Long doesn’t exactly buy the idea that turkey vultures poop on their legs as an extension of this microbial warfare. The problem, he said, is that the bird’s legs don’t have a lot of contact with the carcasses. Their faces, on the other hand, are covered with germs. The vultures have a hard time breaking through tough animal hides, so they frequently find one opening—yes, sometimes it’s the anus—where they insert their heads. One study found 528 different types of microorganisms on turkey vultures’ faces (compared to just 76 in their guts). “Maybe their poop kills germs, but most of the germ contact is on the face,” he said. “So if that’s the explanation, they should be pooping on their faces.”
They don’t do that. Another theory bites the dust.
Vulture Vomit
A turkey vulture has barfed on Long, providing him with a firsthand experience of the stomach detoxification process.
“It smells absolutely abhorrent,” he said. “It’s hard to wash off your hands. It’s one of those smells you wash three or four times and it’s still there.”
“And it smells like rotten meat?” I guessed.
“It’s rotten meat, plus. Maybe it’s that super enzyme they have in their stomachs, or maybe it’s some sort of beneficial bacterial. It’s penetrating, and super distinctive—a special turkey vulture smell.”
It was one turkey vulture in particular that would puke on Long. One of the birds in his colony had imprinted on humans when it was young, and it acted more like a puppy than a vulture. It would affectionately lean on you, Long said, and begged to be scratched on the neck. Turkey vultures in the wild are almost asocial: They roost in groups, but they don’t interact with, talk with, or preen each other. But they are also very clever, and this particular bird had simply learned how to emote in a way that humans could understand.
In any case, Long would take this bird to demonstrations and school lectures. He’d simply put it in the back seat of the car, which always worked fine unless he had to drive a particularly windy road. Then it would get carsick and vomit, and the whole car would stink for weeks.
Turkey vultures seem to use their vomit as a form of defense. If threatened by a larger animal, they will extend their wings and hiss. If this doesn’t work, they vomit up their last meal. This may startle the aggressor, or it may simply lighten their load so they can take to the air more easily. It might also be an offering: Eat this, not me. Long has seen coyotes surprise turkey vultures with what appears to be intention and then gobble up the smelly regurgitated mess. Isn’t nature beautiful?
Unorthodox Perfume
Why, then, do turkey vultures poop on their legs? The short answer is that no one knows. It’s another secret hiding in plain sight. Long does have a hunch; he calls it a “crazy idea” to make it perfectly clear that he hasn’t tested it in any scientific way. But he has spent enough time watching turkey vultures to have a sense of how they work and suspect it may have something to do with signalling identity.
The birds he kept on the roof of the California Academy of Sciences all looked very similar, but he said “it was easy to tell which was which from their personalities.” There was Friendly the affectionate bird, Tennessee Jack the delinquent teenager that loved running behind houses at night and stealing dog food until someone caught it with a pool net, Lumpy, Droopy, and Maggie, who was alert and ornery. The five of them were all intelligent, curious, and incredibly destructive when bored. (“They figured out how to dig up the wood chips, and then found the corner of the tarp under that, and then they peeled the tar paper off the roof,” Long remembered. “So I would have to do things like bury dead rats under layers of cardboard to keep them occupied.”) And he noticed that whenever the birds encoun
tered each other, each would lower their heads to the level of the other’s legs. Were they sniffing?
Though Long could easily recognize the birds by name, they didn’t know if they were male or female. There’s simply no way to tell the sex from the outside, Long said. Then, for an experiment that required that information, Long had a veterinarian make a small incision to find out what kind of sex organs each bird had. Long and the other researchers had, out of force of habit, started calling some birds “him,” and others “her,” but when the results came in they found that they’d assumed the wrong sex for every bird except one.
If the researchers had such a hard time sexing the birds, how did the turkey vultures themselves do it? Perhaps—and Long reminded me that this was “just a crazy idea”—they were smelling each other’s legs to determine who was a male and who was a female. Maybe there is some revealingly fragrant hormone in turkey vulture feces, which they deliberately apply to their legs.
This doesn’t seem so crazy. Any woman who has ever walked into a heavily used men’s room can tell you that male urine smells different. Transgender people undergoing testosterone therapy to transition from female to male have noted the same thing. But Long’s turkey vulture hypothesis will remain a crazy idea until someone has the time and money to figure it out. Like so many other basic facts about turkey vultures, it’s a mystery tantalizingly close to resolution.
After a couple of beers, I’d exhausted Long’s well of facts. “We need more science,” he said with a shrug. And if anyone wants to study them, they are right outside. Just look up.
A not-so-secret part of me wants Josephine to grow up to be the sort of science whiz who might solve these vitally important mysteries, but turkey vulture–watching was pretty boring for her. I’d point one out and she would spot the bird, but after about a minute she’d ask, “When will it find a dead animal?”
Unless you are lucky enough to stumble upon a roost or a carcass, you aren’t likely to see more from a turkey vulture than endless circling. I love seeing them do that; I like to imagine they are sweeping calligraphy across the sky. Nonetheless, I don’t have enough patience to decode this script, and Josephine has even less. So I moved our bird-watching inside, where we found more exciting footage on the computer: A turkey vulture eating a fish, a raccoon, a flattened squirrel.
“Would you like some dead squirrel guts to eat?” I asked Josephine.
She twisted around in my lap and smiled at me. “Can we be a turkey vulture family?” she asked.
Sure, of course.
She slid to the floor and ran into the dining room, waving her arms. “Flap, flap, flap, glide!” she chanted. I followed her, doing my best impression of the terrifying turkey vulture hiss-scream. Josephine pointed toward the window seat: “Look, Papa Turkey Vulture, a dead squirrel! And a dead hamster!”
We ate them all, leaving only the bones.
RESILIENT TRAVELERS
Once upon a time, around the last ice age, there were many more large mammals in the Americas. There were mammoths, mastodons, three species of bison, giant sloths, and giant camels. Back then, there was a lot more dead meat around, and there were many more kinds of vultures to eat it: There are several extinct teratorns, as researchers named them, including one species with an eighteen-foot wingspan, and another (in South America) that weighed up to 175 pounds. Those big mammals went extinct (humans, or an asteroid, or some combination may have killed them), and when those meat sources disappeared, the vultures died out too. There are just three species left in North America: California condors, which are barely hanging on; black vultures inhabiting the southeastern United States and Mexico; and turkey vultures, which have been the most adept survivors. You’ll see them everywhere from Patagonia to Alaska. They had stayed away from the far north, but as climate change warms the world there are reports from Inuit people in northern Nunavut of “bald ravens,” which have turned out to be a new (and apt) name for turkey vultures.
Those birds not only adapt well to change, they seem to thrive on it. When white people wiped out the buffalo, turkey vultures transitioned to feeding on dead farm animals and scraps from slaughterhouses. With the inventions of the automobile and the modern landfill, turkey vultures expertly flexed to exploit these new food sources.
Their strategy for survival is travel light. Though they look big, their body mass is low: They weigh only three to six pounds. They have hardly any fat reserves. When gliding during the day, they burn barely any energy. If they are low on calories they go into a state of torpor at night, their body temperature and metabolism plummeting, their heart rate and digestion slowing down. They aren’t muscular and fast like hawks, and they don’t have a cushion of fat to see them through hard times like ducks do. Instead, they’ve thrived for thousands of years by carrying as little baggage as possible. These introverts of the avian world, so lacking in social graces, have no use for excess or flamboyancy. And so we ignore them. Watch turkey vultures and they’ll show you how the invisible currents of air cascade through the sky, and where some other unseen animal has recently met its end. But mostly, turkey vultures remain a symbol of mystery. When the world surrounding the pattern of work, sleep, and commute starts to feel desperately straightforward and lacking in mystery, just look up at the bird kiting a clean line through the sky and remind yourself: There goes one of the great enigmas of the natural world.
ANT
Once I became a father, I started noticing insects (or “itty bugs,” as Josephine called them), because I was spending a lot more time close to the ground. Moving your face into close proximity with the earth is the key to knowing insects, says Brian Fisher, an ant specialist at the California Academy of Sciences. “You have to go outside, just get a quarter of an inch above the ground, and watch them,” he said. “And you’ll see a whole new world opening up. This small world of insects is actually what’s holding our society together.”
This isn’t hyperbole. E. O. Wilson, the patriarch of ant science, has said that insects are so important that if all the land arthropods disappeared, humans wouldn’t be able to survive for more than a few days. But we are mostly unaware of the ways in which insects support us, not to mention all the cool stuff they do.
No matter where you are right now, if you walk outside looking for wildlife, the first animal you’ll find is likely to be an insect, perhaps an ant. Ants are everywhere, in such abundance that we tune them out like we tune out traffic noise. Lean on a tree for a while and, whether you are in Cincinnati or Kamchatka, eventually you’ll catch yourself brushing an ant off your hand. Get down on your haunches to examine any patch of lawn, or woods, or pavement, and sooner or later you’ll find ants. Scientists doing back-of-the-napkin math have estimated that the total weight of ants is about equal to the total weight of humanity.
When I started trying to gain some familiarity and sense of neighborly understanding with my local ants, I hit a barrier that I hadn’t encountered before: too much information. I could handle pigeons or ginkgos because that was only one species at a time. When I began looking at the handful of common squirrel species, I just had to be careful I wasn’t mixing up a quirk of an eastern gray with that of a fox squirrel. But ants contain swarming multitudes. A researcher in 2003 tallied the number of ant species at 11,006. Five years later, another scientist updated the count to 12,467. We know a lot about just a few of these species, and almost nothing about the rest of them. Furthermore, scientists estimate that there are another ten thousand ant species waiting to be discovered. Anyone who wants to learn about these most common of insects faces a high hurdle: There are libraries full of information about ants, and yet that’s barely the beginning of what there is to learn.
The vastness of the world of ants is an impediment for beginners, but it’s also an enticement: It means that the unknown is waiting right there in the park and in the driveway, ripe for discovery. This quotidian exploration doesn’t seem as exciting as trekking through jungles and seeking hidden empires, b
ut people who have had the full range of these experiences say they are much more similar than you’d expect.
As a kid, scientist Rob Dunn dreamed of journeying into the unknown, and as a biologist, he’s actually gotten to do that. He has explored tropical forests and discovered things previously unknown to science. Having experienced all that, however, he reports that he now finds backyards even more fantastical. “New species, and even whole societies remain to be studied in the dirt beneath our feet,” Dunn wrote. “Among the least explored empires are those of the ants.”
WHAT KIND OF ANTS?
The first step, I figured, was to make out what type of ants I was dealing with. Scientists at North Carolina State University (NCSU)—where Dunn works—have set up a citizen-science project to identify ants around the United States (schoolofants. org). Its protocol is simple: Break cookies (pecan sandies; I’d learn why later) onto index cards, leave them outside for an hour, then dump all the ants that have accumulated on the cards into bags and send them off to NCSU for identification. I couldn’t find index cards, so Josephine and I cut notebook paper into three-by-five-inch pieces. Using markers, we labeled four “green” and four “paved,” then set out the bait. Josephine intently crumbled the cookies onto the cards. She had never had pecan sandies, and decided that they were strictly for ants. I did my best to preserve that illusion. It seemed like a winning strategy until Josephine told me she’d dumped the entire box of cookies outside, to facilitate our collection.
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