The Bird Way: A New Look at How Birds Talk, Work, Play, Parent, and Think

by Jennifer Ackerman

lekking males perch on a special slender twig and vigorously defend their territories by singing while wagging their little white-tipped tails. Most males occupy their singing perches and territories for less than a year, though a few lucky ones may persist as long as seven years. If you’re a young male, it’s hard to win your own territory. Young males seeking to join a lek use their gifts of imitation to impersonate existing territory holders. “First, they’ll sit out on the edges of the lek listening,” explains Kapoor. “Then they’ll sneak around and eavesdrop on different individuals, focusing in on one local bird—let’s call him ‘Fred’—listening to him and learning his song. Then they’ll go off into the forest and practice by themselves. They sound horrible at first, squeaking away, and for the first couple of weeks, you can’t identify what they’re trying to copy.” But the young birds practice and practice, and over the course of a few weeks, they get much better. “By the time a young male is ready to come back and take his place on the lek,” says Kapoor, “he sounds exactly like Fred—or at least, one of his close neighbors—so I know exactly where in the lek he’s intending to go.” And here’s the creepy part: Kapoor suspects that a newcomer “mimic male” may attempt to usurp an established male’s territory by attacking and killing him and then taking his place—if he himself is not killed in the process.

The new-world toad was introduced to Australia in 1935 and spread quickly from Cape York Peninsula to Sydney and west beyond Darwin, bringing death to predators unfamiliar with its venom. Over just a few decades, pied butcherbirds, along with a few other clever species—Torresian crows, black kites, pied currawongs, white ibises—discovered the trick of avoiding the toad’s poisonous parts, the glands on the back of its head and the skin itself. Otherwise the toad is well worth eating. Their technique: flipping over the toad and eating from the belly side inward. Ibises consume only the toad’s legs. Black kites eat only the tongue.

Vultures are nature’s sanitary workers. Because they feed in groups and eat rapidly—each bird downing more than two pounds of meat a minute—they can rapidly consume whole carcasses. Their guts are acidic enough to destroy the agents of disease, such as cholera and anthrax, so there’s little risk of spreading contamination from an infected carcass. That’s not the case with more leisurely mammalian carrion eaters such as rats or dogs or coyotes. What happens when vultures vanish, people learned the hard way in India and Pakistan more than a decade ago. There, a mass die-off of old-world vultures caused by an arthritis drug in the flesh of dead cattle led to an eruption of rabies. Dogs took over feeding on the carcasses, and the canine population exploded, along with the spread of the deadly disease.

Birds top us in color vision, too. They see hues beyond our imagining. Humans have three types of color-receptive cones in our retinas, blue, green, and red. Birds have a fourth color cone that is sensitive to ultraviolet wavelengths. We are thus “trichromatic,” and most diurnal birds are “tetrachromatic.” With their extra UV cone, birds can distinguish shades of color we can’t tell apart, allowing them to spot prey well camouflaged against the uniform background of a grassy field or leafy forest floor, and to detect things invisible to us—like the trail of urine left by a vole.

The facial disc—the circle of feathers around each eye—acts as a pinna or dish antenna, directing sound to the owl’s colossal and complex ear openings, which are asymmetrical; the left ear opening is farther upward than the right. This asymmetry allows the owl to pinpoint the direction of a sound from its perch. And also, to locate prey in total darkness, as a barn owl does, with an error of less than one degree. The

Unlike bats, which emit sounds at ultrasonic frequencies too high for us to hear, oilbirds emit audible clicks, which bounce off objects and provide an auditory map of their surroundings in the dark.

Audubon’s experiment was a little like serving your cocktail guests fetid oysters and surmising they don’t have a taste for seafood. The results were “fully conclusive,” he said. “The power of smelling in these birds has been grossly exaggerated.” Later observers following Audubon’s lead went out of their way to explain how turkey vultures might find hidden food by any means other than smell. By watching or listening for the buzzing of flies, for instance, or by observing the movements of carrion-eating mice and ground squirrels scurrying to and from a concealed carcass, or domestic dogs sniffing it out with their keen noses. Vultures perhaps have such big olfactory bulbs not to spot prey, they theorized, but to detect the direction and quality of air currents for soaring. Fortunately, Betsy Bang came along to crush Audubon’s theory. Bang, a scientific illustrator at Johns Hopkins University in the late 1950s, dissected and sketched the nasal cavities of various bird species to illustrate her veterinarian husband’s articles on respiratory disease in birds.

Stager also identified the specific scent that drew vultures to carrion. The discovery arose from a serendipitous conversation with field engineers at an oil company, who had been aware for some time that turkey vultures have knowing noses, and used the birds to locate leaks in natural gas lines. The engineers had figured out that if they introduced ethyl mercaptan into the line, they could locate leaks by the concentrations of turkey vultures circling above the line or sitting on the ground next to it. The same sulfurous chemical added to natural gas so the human nose can detect a leak, it turns out, is also released by an animal shortly after it dies. Thanks to Stager’s experiments, we now know that turkey vultures are highly attracted to the scent and can use it to find a target as tiny as a dead vole buried in leaves on the forest floor beneath a thick canopy of trees.

Detailed comparative bird brain studies like Bernice Wenzel’s revealed that olfactory tissue takes up about 37 percent of a seabird’s brain, versus about 3 percent in the brain of a typical songbird. Moreover, the olfactory bulbs of some seabirds have twice as many mitral cells as rats and six times as many as mice.

By sniffing out scented compounds—one chemical in particular, dimethyl sulfide, or DMS, generated when krill devour phytoplankton. Over the past two decades, Nevitt has parsed the impressive ability of seabirds to detect tiny amounts of the chemical. To our noses, DMS is that sulfury, briny smell of the seashore or oysters on the half shell. To seabirds, it’s the scent of sustenance. “Birds tend to be attracted not to prey scents per se,” she says, “but rather to odors such as DMS that are released during feeding interactions”—a euphemistic term for the ravaging of prey by predators. In other words, says Nevitt, “predators tend to be messy eaters, and tube-nosed seabirds have adapted to pay attention to who is eating whom.”

Guanay cormorants, which live and nest in colonies along the Peruvian coast, form a floating raft of birds that shifts in orientation continuously over the course of the day to indicate the direction of ephemeral prey patches. Every cormorant leaving the colony to fish joins the raft for guidance before heading for feeding grounds.

Herons all over the world have learned to bait their catches, carefully placing leaves and dead insects on the surface of the water to lure fish. Pied kingfishers, black-crowned night herons, and green herons living in parks have learned that the bread people throw to ducks and geese will also draw minnows. They’ve taken to plucking up bits of bread and placing them on the water, then waiting with Job-like patience for a minnow to nibble and seizing it with a rapid thrust of their long, sharp bills.

Some birds get at food enclosed in hard shells or other tough packaging by dropping it on pavement to crack it open. Gulls drop clams, and crows and ravens drop nuts. Perhaps most notable is the lammergeier, or bearded vulture, a carrion-eating bird like the turkey vulture, but one that feasts on bones rather than flesh. Small bones it swallows whole; large femurs and ulnas it takes to the sky, letting them go from hundreds of feet over rocky outcrops to split them open and release the marrow. It has its favorite spots for bone breaking, known as ossuaries. This huge and lovely bird is thought to be the one that killed Aeschylus when it dropped a tortoise on the Greek playwright, mistaking his bald head for a stone.

The most famous tool user of the bird world is the New Caledonian crow, featured in The Genius of Birds. This crow makes and keeps its own highly sophisticated tools. It’s the only species other than humans to make and use hook tools, little sticks with a hook on the end, which the bird uses to extract grubs and other invertebrates from tree holes and the nooks and crannies of plants. The crows also make very elaborate hooked tools from the leaves of pandanus trees. Pandanus leaves have little barbs along the edge, which the bird uses to latch onto its grubs. It takes a lot of complicated steps to make these tools. The birds make several methodical cuts and tears in the leaf before removing the fully crafted tool from the leaf. This suggests they have an image of the tool in their heads before they actually start making it.

With no training or guidance, four of the crows put together the pieces within five minutes and used the longer compound pole to reach and extract the food. One bird was able to combine three or four elements to make one long tool—the first evidence of compound-tool construction with more than two elements in any nonhuman animal. This is truly a staggering accomplishment. Children can’t make these sorts of multipart tools until at least age five.

It’s one thing to exploit an already raging fire; it’s quite another to start one yourself. But at least three species of raptors in northern Australia seem to be doing exactly that. Like raptors elsewhere in the world, fire hawks, as they’re called collectively—black kites, brown falcons, and whistling kites—hunt in the vicinity of bushfires. But witnesses have observed these birds doing something radically different: flying into active fires, picking up smoldering sticks, and then dropping them in unburned brush or grass, spreading the flames to new areas, presumably to flush out prey.

Studies have shown that birds can pick up novel strategies for foraging within a bird community and pass them around through social networks until they become established behaviors. The classic example of this cultural learning was first noted in the British Isles in the 1920s: A group of great tits, a species known for its superb problem-solving skills, discovered that if they peeled off the foil cap from milk bottles left on doorsteps, they could glean a rich meal from the lovely cream that collects at the top.

The ants are Eciton burchellii, the mini-lions of Costa Rica’s neotropical forest, ferocious pincer-jawed predators that capture nearly every arthropod in their path. They’re pouring out of a huge temporary nest site known as a bivouac. The nest is made of the bodies of live ants themselves linked to one another by their own limbs, creating a huge, jiggling, thermoregulated sanctuary for the queen and her larvae.

A huge diversity of birds attend these ant raids to find their daily food—as many as a hundred species at a given location. Among them are species of rainforest birds so dependent on the ants and so specialized to find and follow them that the tiny insects are built right into their names:

None of these birds are silly enough to eat the ants themselves. Rather, they mooch off the ants’ labors, swooping down and picking off creatures the ants have rustled out of hiding. It’s a good example of kleptoparasitism, that form of freebooted feeding in which one animal takes food that was caught, collected, or prepared by another.

O. Wilson tells the story of allowing driver ants to sweep through his critter-infested house in Gorongosa National Park in Mozambique on a regular basis. “You just go away and have a cold drink somewhere,” Wilson says. And after a few hours, the army has passed through, massacring and taking with it every animal it finds. Then “you can return home—a home that has been perfectly cleaned for you.”

birds attending ant raids are not so much competing as coexisting, sharing resources, perhaps even facilitating one another’s participation—deliberately or not. “Having other birds around may be an advantage because there are more eyes and ears to detect predators,” he says. “Food is usually abundant at a raid, so the costs of allowing other birds to attend may be low, favoring more positive interactions.”

antbirds visit multiple ant colonies in a single day to keep track of different bivouac and raid locations and what the ants are up to there.

If the ants are in the midst of moving to a new bivouac site, the bird follows the immigration column from the old site to the new site. “In a sense, it’s putting the ants to bed before returning to its roost,” says O’Donnell, “which is what researchers do.” Early the next morning, the bird flies directly to the bivouac, lands on a nearby perch, sometimes only inches from the ants, and peers into the bivouac and the ground around it to assess the ants’ activity. If the ants are raiding, the bird will track the raid to its front and forage there; if there is no activity, it will move on to another bivouac to check its raiding status.

Just before it left a bivouac site, the bird would sing a loud song, probably directed at its mate, which acts as a “departure signal,” says Chaves-Campos. The other ocellated antbirds present at the site, eavesdropping on the signal, would depart, too, and travel silently through the rainforest, moving single-file directly to a new site, each bird separated by a few seconds like orderly kindergarteners on a city walk. No meandering in different directions, just a beeline from one site to the next, as if one or more of the birds in the group already knew the exact location. Which, it turns out, they do. In one instance, an antbird in a group traveled directly to a new nomadic ant colony that this particular bird had not itself inspected on the previous evening. Other group members had scoped it out while the ants were moving their nest overnight to a new location, one hundred meters away from the old one. In each of the three trips from site to site, all of the birds in the group traveled directly and arrived simultaneously, within ten seconds, at the new site. “This suggests that these birds do not wander looking for ant colonies,” says Chaves-Campos. “They know where to go, or at least one individual in each travel group knows the location of the colony. By following those who know, the antbirds discover ant colonies previously unknown to them.”

When a hummingbird drains nectar from a flower, it takes time for that flower to replenish its supply. Visit the same bloom too soon, and it will still be empty; wait too long, and a competitor may make off with your precious drink. You must remember what flowers you’ve visited and when—in fields with thousands of flowers. It’s like a giant game of Concentration.

Moreover, bivouac-checking birds show signs of behaviors that may signal planning. When an antbird checks a bivouac in the evening after a day of gorging, it does not feed; it’s just gathering information. Only in the morning, when the bird returns to the location it discovered the night before and finds the ants swarming again does it encounter its reward—the bounty from a fresh raid. In other words, the antbirds are not responding to their current state (satiation), but rather a future need (breakfast!), which suggests they may be anticipating a future event: “Check location of bivouac now in anticipation of foraging the next morning.”

As one of the most playful animals on the planet, ravens embody a mystery. Play is a strange behavior in any animal, says Osvath. “There are so many good reasons not to do it.” It takes a lot of energy that could be used for other purposes—growing, for instance. It’s also inherently risky. “If you’re out in the wild, and everyone is playing, then no one is paying attention to any potential threat. A bird at play is particularly conspicuous to predators, which are never far away.” The behavior seems at best extravagant; at worst, downright dangerous. “Out in the wild, playing must be very important,” says Osvath. “Otherwise, why would you make yourself vulnerable in this way? It’s a world of eagles, owls, even wolves out there. Distraction at the wrong moment could mean the end of you.”

Doing science with ravens, on the other hand, is easy. “They’re so inquisitive and engaged,” says Osvath. “If they find that a task is interesting enough, they’ll line up to participate. They’re fun to study, and they make me laugh.” They’re also as knotty and contradictory as any character from Shakespeare. They’re highly intellectual birds, yet often silly in their antics. They have a strict, rigid social hierarchy and pecking order maintained through conflicts and fighting—they form coalitions and beat up on one another—and yet they continue to frolic together well into adulthood. They love to noodle around with objects yet seem deathly afraid of them—at least when they’re new. “If you put a chair in the aviary, for example,” says Osvath, “the birds will sit and look at it for two weeks. And then, all of a sudden, they’ll go for it, and it will take them like five minutes to completely dismember it. You never know what will scare them. You can think, ‘Oh, when I bring in this new experimental device, they’ll just freak out. But they don’t. And then one day when you walk into the aviary, they completely lose it, and you can’t understand what the problem is, until you realize, ‘Oh, I’m wearing new gloves.’

There’s a seventh raven on the premises, but she’s wild. “She doesn’t understand that she’s wild, so she hangs around,” says Osvath. “And when we do experiments, we open the aviary, and she just comes in, participates, and then at the end, walks out. In the ethics section of grant applications, it’s difficult to explain: She’s wild, but her participation is completely voluntary.”

Among Osvath’s more striking studies is one that appears to propel ravens into that exclusive clutch of animals—apes and scrub jays—that may use past experience to plan for the future. Osvath and a graduate student, Can Kabadayi, taught five ravens how to use a special tool—a stone of a specific weight and shape—to open a puzzle-like box containing a high-value treat. Though ravens are not tool users by nature, the birds were quick studies, requiring only one lesson to learn the trick—“a single observation of tool use by a non-tool-using species!” Osvath exclaims. When the experimenters took the box away and presented the ravens with a choice of objects, only one of which was the functional tool that could open the box, the birds picked the object that would be most useful to them if that treat-laden puzzle box reappeared in the future. They could wait as long as seventeen hours and would do so even when they were offered an inferior treat immediately; despite the temptation, the birds didn’t bite on the lesser alternative. Instead, they chose the special tool and saved it to secure the later, tastier reward.

In fact, play is most often defined by what it is not: It is behavior that is not purposeful, serves no obvious adaptive function, does nothing to enhance an animal’s chance of survival and reproduction—nothing apparent, at least.

ravens will guard their caches against discovery in response to the sound of another raven in an adjacent room—but only when a peephole between the rooms is open and not when it’s closed. This suggests that ravens are more than mere “behavior-readers” and can take the perspective of another bird, holding in mind what another creature can or cannot see—which some scientists consider a critical component of the sophisticated cognitive ability known as theory of mind.

If one raven was engaging in object play, another might start doing locomotor play, and still others, social play. “It’s the play mood that seemed to be contagious,” says Osvath. Positive emotional contagion is also found in other animal species—chimps and rats, for instance. Scientists have lately found that negative emotions in ravens can be contagious, too. When a raven sees allies struggle with a task that denies them a treat or sees their disappointment in response to unappetizing food—but not the food itself—its own interest in food diminishes. This kind of emotional contagion, whether positive or negative, is considered a building block of empathy.

Laboratory rats deprived of play don’t develop normal brains.

“Do birds have the capacity for fun?”, cognitive scientists and corvid experts Nathan Emery and Nicola Clayton cautiously suggest that the answer is yes. In most animals, play seems to be a powerful trigger for the release of dopamine, which is active in the reward system in the brain, and also for endogenous opioids, which are essential for sensations of pleasure.

Ravens and kea are considered the two most playful birds on the planet,

This difference—the ravens being drawn to what they know, and the kea, to what they don’t know, to new and novel things—makes a huge difference in how they behave and actually means that we must be very careful in designing our experiments and interpreting behaviors.

Out of nearly twenty-five thousand calls he recorded, only twenty-four were this whistle. Schwing believes it’s a very personal communication between one bird and another that seems to say, “I want to have close contact.” A video he took of the whistle call shows a male perched on a bench. A female lands and moves toward him to preen him, but he kicks her away. She jumps back and then whistles quietly. He immediately lowers his head and allows her to come in and preen him.

Studies show that most animals prefer some sort of foraging challenge. Cats, for instance, love food puzzles—gadgets that engage their hunting instincts and encourage physical activity—and this has been found to reduce their stress.

“Cluing into the kea’s smarts at social learning might actually benefit the sheep farmer,” says Schwing. The best way to deal with kea attacking your sheep? “Remove the young male that has started the practice of feeding on the sheep before it spreads as knowledge within the group,” he advises. “If you move that young male—and it’s almost always a young male, what we call an ‘innovator personality’—sheep and birds can live again peacefully until the next young male comes along to innovate.”

“Kea just have this built-in ‘juveniles go first’ mentality,” says Schwing. “We see it in captive populations; we see it in the wild. Juveniles and fledglings can walk up to any bird and just take food away from them.”

https://youtu.be/N37rN29nUIc

Birds deprived of play in youth will not play in adulthood—and may struggle to fit into social groupings.

people too

Scientists suspect that laughter may have evolved from the breathy panting and labored breathing during play fighting and tickling between our primate ancestors and was used as a signal that everything is fine, now is a good time to socialize, play, explore together.

the pair plans to test kea to find out whether warbling might shift the birds’ mental state to make them more optimistic, as laughter does for us. This may seem like anthropomorphizing, projecting human experience onto an animal’s behavior, but it turns out there is a solid, well-established test for optimism in animals. Here’s the kea version: The bird is taught that a big box always contains food and a little one does not. Then a midsize box shows up. “An optimistic animal will take a ‘glass half-full’ perspective,” says Taylor, “and assume that the medium box is like the big one and will run right up to it.”

At first blush, their reproductive organs seem all alike. Both male and female have a cloaca, an opening that in the male swells during the mating season, projecting outside their bodies. When birds mate, they briefly rub together their swollen cloacae, allowing the male’s sperm to move from his cloaca to hers and then travel up her reproductive tract to fertilize her egg. (Bird cloacae also have a decidedly less sexy role: to excrete urine and feces.)

Most birds have no penis. But there are exceptions. Several species of ducks, geese, and swans have an organ like a human penis, which is inserted into the female. These waterfowl belong to the 3 percent of living bird species that retain the phallus found in their reptilian ancestors. Some ducks—such as those brutish male mallards—have impressive counterclockwise corkscrew-shaped, snakelike phalluses that grow as long as their bodies, which they use to deposit sperm as far as possible inside the female reproductive tract, to better their chances of fertilizing her eggs.

Concealing sex is thought to be pretty consistent across human cultures. The Yanomami of Venezuela, for instance, arrange trysts away from villages and out of the public eye. Married Malekula couples of Melanesia return home from a rendezvous in different directions. And Mehinaku couples in Brazil have sex only in secret locations. In fact, the penchant for private sex has been considered a universal human trait and one that may have influenced the evolution of human emotions and advanced cognition.

The truth is, plenty of birds interact sexually with dead members of their own species. The behavior has been noted in bridled terns, European swallows, sand martins, and Stark’s larks. It’s not at all the same as a human having sex with a corpse