Whitefeather and Goliath then flew outside, where Whitefeather showed that she was upset by uttering alarm calls, hammering on branches, and hanging upside down by her feet. “I had never seen her do either of these behaviors before,” Heinrich writes. (Should you see me hanging upside down by my feet after you have been switching my kids in the cradle, take it as a sign that I am very upset indeed.) Cleverly, Heinrich changed the subject by producing some tasty road-kill, and both parents got busy bringing meat to the nest and feeding the chicks. Heinrich then returned the original two chicks, so that Goliath and Whitefeather now had six babies of two different ages. Having gotten over her initial unhappiness, Whitefeather now cared for all six, showing no favoritism.
Master criminal seeks same
Nest parasites face a difficult situation in figuring out their species identity, and it’s all their parents’ fault. Having been born to families of crooks, but raised by honest citizens, they must manage to be successful crooks themselves without the tuition of master criminals. How can they find the right accomplice?
The answer is probably different for different species of nest parasites. It has only recently begun to be pieced together. Mark Hauber and colleagues have proposed that nest parasites need a password to recognize each other. This password could be a call, a display, or some other form of behavior that the species innately knows how to perform and to recognize. The password triggers learning, so that when a strange creature gives the password, the recipient learns that this is a creature of its own species.
Great party! Who is everybody?
Cowbirds don’t seem to imprint on their adoptive parents. When they grow up, the females lay their eggs in suitable nests of a variety of species and do not confine themselves to the species that raised them.
When they leave the care of the suckers who raised them, they join large flocks of other teenaged cowbirds. How do they know to do this? Hauber and colleagues Stefani Russo and Paul Sherman suggest that the cowbird chatter call is the password that attracts them to the juvenile flocks. At all times of year, both males and females utter chatter calls, which don’t seem to be learned. In the laboratory, nestling and fledgling cowbirds who had never heard cowbird calls showed interest in playbacks of chatter calls. The nestlings begged twice as much to chatter calls as to other cowbird calls or to the calls of other species. Fledglings approached speakers playing chatter calls more quickly than they approached speakers playing sparrow songs.
In addition, cowbirds may notice their own appearance, and perhaps look for birds who look like them. Young cowbirds are gray and streaky. When researchers gave some captive cowbirds black streaks in their plumage by coloring each pinfeather with a black marker as it emerged, the birds apparently concluded that cowbirds are supposed to have black streaks. When they were older and met both normal cowbirds and cowbirds with black streaks drawn on their plumage, they courted the black-streaked ones.
In the wild juvenile flocks, the cowbirds are among their own kind for the first time. This is the time in their life when they learn, through imprinting, who might make an attractive mate. If, in captivity, you keep young male cowbirds with canaries during this juvenile period, they will court canaries when they are older, even with lovely female cowbirds standing by.
They also learn how to act. Female cowbirds, even raised in isolation, respond to male cowbirds’ song, and they indicate their opinion of it, phrase by phrase, with little wing quivers. In this way, females teach the males to perfect their songs (assuming the males are not too smitten with canaries to look at them).
So, step by step, genetic information interlocking with learned information, cowbird meets cowbird, and they continue the unscrupulous careers of parents they never met.
Other nest parasites
Great-spotted cuckoo mothers apparently return to the nests where they laid their eggs and chatter at their chicks. “That’s not your real father feeding you! That’s not your real mother! I’m your mother and this is what I look like! This is what I sound like! Whoops, gotta go.”
This species of cuckoo has refined its criminality to a remarkable extent, at least in southern Spain, where its wicked ways were studied by Manuel Soler and colleagues. Researchers had noticed that in nests where magpies had detected and tossed out a cuckoo egg, bad things were likely to happen. The “Mafia hypothesis” suggests that if magpies do not accept a cuckoo egg laid in their nest, the cuckoos will notice and may come back and destroy the magpies’ own eggs.
The experimenters tried tracking the fate of parasitized magpie nests from which the humans themselves had taken the cuckoo egg. Sure enough, more than half of the clutches (as opposed to 10 percent of the nests they left alone) were destroyed either as eggs or chicks. In one case a female cuckoo was spotted pecking the magpie eggs.
Remarkably, the point of this seems to be that it teaches the magpies a lesson. Magpies who had tossed out a cuckoo egg and then had their nest destroyed were more likely to let the cuckoo egg stay the next time they built a nest.
The good news for friends of freedom is that the Mafia tactic seems to be losing ground. In the magpie population as a whole the tendency to toss out cuckoo eggs is slowly increasing. “Just as the human Mafia might find it easier to control some victims than others, so Mafia cuckoos might be better able to control particular host individuals, say those that are less able to defend their nests, or those with fewer reproductive opportunities elsewhere,” writes N. B. Davies in Cuckoos, Cowbirds and Other Cheats. “So we may find some individual hosts in a population that do not submit to cuckoo control, and reject cuckoo eggs, while others are forced to accept to make the best of their poor circumstances.”
It’s hard enough trying to raise this kid without worrying about its looks
Birds that are nest parasites don’t have to look too hard to find another species of bird qualified to (unknowingly) babysit. But most animals are ill equipped to raise a baby not their own, or to be raised by a parent of another species. In Kenya, in Samburu National Wildlife Reserve, a young lioness tried desperately to be a mother to an oryx calf, and the calf did its best to be her child, but the attempt was doomed.
This mysterious pairing was seen by hundreds of Kenyans and visitors to the reserve, and was recorded by Saba and Dudu Douglas-Hamilton, sisters who are wildlife photographers and documentary filmmakers associated with Save the Elephants.
The pair was first seen together in December 2001. The oryx calf was very young and still had its umbilical cord. The lioness was two or three years old and showed no signs of having had cubs. She had formerly spent much of her time with her sister, but now she seemed to care for nothing but the calf. They were constantly together, with the lioness licking the calf and rubbing her head against it, and the calf nibbling on the lioness’s ears and trying to suckle from her. “They did everything together, walked, slept, groomed, drank from the river,” wrote Saba Douglas-Hamilton.
How the two of them met and how the lioness came to think of the calf as her child is unknown. A mother oryx goes away from the herd to give birth. She visits it a few times a day to feed the calf and after two or three weeks it joins the herd with her. Perhaps the lioness found the calf alone and somehow, in an atypical example of maternal imprinting, perceived it as a baby needing love and protection rather than as a quick snack. The calf was seen approaching other oryx, and rangers reported that it had suckled from one. The lioness couldn’t feed it herself. When the calf approached other oryx, the lioness would watch worriedly from a distance, and if the calf moved off with the other oryx, she would follow—which would frighten the adult oryx into running away.
During the weeks they were together, the lioness didn’t hunt, and grew thin. Once she was seen stalking a warthog, but broke off to race back to the calf. Another time, it is reported, she started hunting and cheetahs zoomed in and grabbed the calf—but the lioness spotted them, ran back, and drove the cheetahs away.
Two week later, the lioness and the c
alf were seen drinking from a river together. They were resting in some bushes, and the calf went around a bush and was seized and killed by a lion from another pride. The distressed lioness could do nothing to save the calf.
Not long afterward, the lioness was seen with another calf. After a week, the undernourished calf was taken away from her and brought to a game sanctuary to be fed and returned to its oryx mother. The lioness was then said to be following the oryx herds, apparently in search of a new child. Others said that people who wanted to benefit from the crowds of tourists who came to the reserve to see the lion lie down with the calf had provided the lioness with the second calf themselves. Whether or not she was supplied with the calf by unscrupulous persons, the fact remains that she fell for it. Try that with any ordinary lioness and the response would be less cute. By February 2003 the lioness, now named Kamuniak, had tried to adopt six oryx calves and one impala calf.
During the time that the lioness and the calf were together, many people puzzled over a way to support their relationship. If they supplied the calf with milk, could the strange pair succeed? If the lioness had been able to suckle the calf, could she have protected it long enough for it to become independent? Lion cubs are usually brought to join a pride of lions after they’re about six weeks old, and are protected by the pride. It seems unlikely that the lioness’s pride would have extended their affection to her strange baby.
Although the two seemed to love each other, they didn’t understand each other well. “As if it were an autistic child, the lioness was unable to communicate with it, and she had no choice but to follow dotingly wherever it went,” wrote Saba and Dudu Douglas-Hamilton.
A lioness in Tanzania observed by Elizabeth Marshall Thomas started to eat a dead wildebeest partly eaten by another lioness and uncovered “a full-term dead fetus.” She removed it, and began tenderly licking it. “Gently and carefully, she cleaned its face by removing and swallowing the caul, then cut the umbilical cord, and licked the stump. Having done everything necessary to deliver the fetus safely, she ate it.” Thomas points out that a lioness typically eats a lion cub that is stillborn, too. What if the wildebeest calf had been alive? Perhaps the train of maternal behavior that the lioness showed would have continued, and she would have treated the wildebeest as her baby.
George Schaller has described lost wildebeest calves, looking for someone to follow, who persistently followed lions. These incidents worked out as you might normally expect—badly for the wildebeest, excellently for the lions.
Soar like a goose, splash like an eagle
A somewhat more successful adoption shows the need of both parent and child to adapt to the other. Lady, a golden eagle raised by Ed and Kent Durden, laid eggs, which she brooded devotedly. The Durdens, taking the view that it was a shame that her maternal attention to the infertile eggs could lead nowhere, stole the eggs and substituted a fertile goose egg taken from one of the big white barnyard geese who lived in a flock down the hill. It was Lady’s habit, when flying free, to swoop down and chase these geese, but she had never caught one.
Lady did not seem to care that her two eagle eggs had turned into a single goose egg. She continued to brood, and soon a gosling could be heard peeping within the egg. Lady chirped encouragingly, and it peeped back. The gosling began the laborious task of fighting its way out of the egg. Lady watched in fond concern and picked away bits of broken eggshell, the duty of either a loving eagle mother or a loving goose mother. Finally the gosling was out, lying damp and exhausted in the bottom of the giant eagle’s nest Lady had constructed in her aviary.
Eaglets stay helpless for weeks, but goslings are up and about in no time. Within the hour the gosling was looking around, peeping. Lady chirped and tore a minute piece of flesh off a chunk of horse meat. She held it in her bill for the gosling to grab. But goslings do not grab meat from their parents’ bills. They pick food—insects, seeds, and vegetation—off the ground and out of the water. The gosling, to Lady’s dismay, began moving about the nest, pecking, looking for food. It was as if a day-old human baby ran over to the refrigerator and began ransacking it. Lady followed, chirping to draw attention to the meat she held. As the gosling sprinted around the nest, peeping about how hungry it was, Lady followed, offering lovely horse meat to her precocious child and being ignored. Ed Durden held the gosling up to Lady’s bill, but the gosling still ignored the meat.
This went on all day, with the gosling getting nothing to eat, and Lady worrying herself into such a state that Ed Durden had to calm her by letting her feed him the horse meat. (She gently laid pieces of horse meat on his nose, and when she glanced away he palmed them.) At night mother and child snuggled up together lovingly, with the gosling tucked under Lady’s feathers in a manner common to both eagles and geese.
The next day the gosling again scoured the nest in search of goose food, while Lady kept cornering him with offers of meat. The Durdens were about to take over feeding the gosling themselves when suddenly a lightbulb lit up in a little balloon over the gosling’s head. “The gosling was looking up at Lady for the first time, instead of looking at the ground. Lady uttered a sound and extended her bill toward the gosling, and he responded as if his eyes had just now been opened. She held her bill still while the gosling picked the meat off the bill and swallowed it with relish. Immediately Lady tore off another piece and this time the gosling was waiting to take it.” The adaptable little goose packed away the meat with pleasure.
Gosling and eagle were now perfectly happy, but after a while the Durdens began to wonder if an all-meat diet was really the best thing for a gosling, and they put a bowl of bread and milk in the aviary. Lady tasted it and thought “Why bother?” but the gosling guzzled delightedly. Lady noticed, and the next time the bread and milk was put in, she gripped an edge of the bowl in her beak, carried it over, and slapped it down in front of the gosling.
The next crisis came when the gosling, who had leapt out of the nest and was speeding around the aviary, spotted Lady’s bathtub. Grown eagles like to bathe, but eaglets don’t do this and might catch cold if they tried. Lady tried to head her child off, but he dodged between her legs and plunged in. He splashed and frolicked as Lady begged him to come out, leaning over the edge of the pool and calling in alarm. He ignored this, so she waded in, giving him the opportunity to dive between her legs and pop up on the other side.
As the gosling grew, the Durdens managed to get more vegetation in his diet, but even as a full-grown goose “he never turned down the chance for flesh food.” Kent Durden writes that he “would tear into meat as ferociously as an eagle, and he could do remarkably well with the tools he was equipped with.” Since Lady’s diet was not confined to horse meat, the goose might be seen “tearing into a jackrabbit, or…trying to swallow a snake.”
Mother and child remained fond, even after he was transferred to the flock with the other geese. Kent Durden describes a day when Lady was flying free. Seeing an eagle overhead, the geese waddled away at top speed, except for Lady’s son, who called to her. She called to him. Calling, she headed for him, and calling, he stood on the grass. (“Mom! Mom! Mom! Mom!”) As she swooped down upon him, he was stricken with instinctive fear, panicked, tried to run, and fell over. (“Help! A monster is attacking me!”) His mother landed beside him and chirped soothingly and all was well. (“Mom! Where were you? A monster attacked me!”)
In later nesting seasons the Durdens supplied Lady with more children: goslings, ducklings, some baby great horned owls (the owlets troubled Lady by staying up all night, so she had to stay awake to keep watch over them), some baby red-tailed hawks, and even a couple of eaglets. She was delighted with them all. After spending 16 years with the Durdens, Lady met a wild male eagle and eloped. She was later seen sitting on a nest on a California cliff, so perhaps her long experience of motherhood stood the species in good stead.
FOUR
How to Get Your Point Across: Being Vocal, Being Verbal, and Otherwise Communicating
&nbs
p; Lucy Temerlin, a chimpanzee raised in the family of psychotherapist Maurice Temerlin, used innate chimpanzee sounds. She made food grunts when stealing yogurt from the refrigerator and said “boo” in a low voice when she saw worrying large animals like horses or cows. She used chimpanzee gestures, like an extended arm with limp hand, to turn away the wrath of a superior.
She was also taught some American Sign Language. One day she committed a crime of vandalism, sneaking into the living room just before a dinner party, pulling the leaves off a potted banana tree Temerlin had put there, tearing apart the trunk, and dumping the soil out of the pot. When Temerlin discovered this, he shouted “Goddamn you!” and raised his hand to belt her. “Instead of extending her pronated wrist, Lucy looked me directly in the eye, smiled her little girl smile, and touched her nose with her thumb, forefinger extended in the ASL sign which means, ‘I’m Lucy.’ I stopped in mid-gesture! I could not hit her, my eloquent chimpanzee daughter.”
MOST ANIMALS ARE BORN knowing what to say. They know how to meow for their mother’s attention, growl to warn another kitten away from their food, or hiss when they fear attack. When another kitten growls, or their mother purrs, they understand what that means. No one has to teach babies to cry, and no one has to teach people to want them not to cry.
Becoming a Tiger: The Education of an Animal Child Page 11