Becoming a Tiger: The Education of an Animal Child Read online

  Dialects

  If you don’t recognize your neighbors as individuals, you may still recognize them as locals if your species has dialects. If it does, and you move after you grow up, you may need to learn the local expressions. Luis Baptista found a white-crown in San Francisco singing an Alaskan dialect which he presumably learned from an Alaskan bird migrating through. A month later, he had a wife, and sang San Francisco songs like his neighbors. Baptista played him recordings of Alaska songs and he acted as if he had never heard such a thing. Finally, the seventieth time Baptista played the Alaska song, the bird replied in kind.

  Observing orange-winged amazon parrots in Trinidad, Fernando and Marta Nottebohm visited an area 30 miles from their usual study site and saw parrots uttering “high-pitched whistling calls…like nothing we had heard before.” Another species? No, another dialect.

  Chimpanzees do not need to learn their calls, yet they can also have dialects. Researchers compared one of the classic chimpanzee calls, the pant-hoot,* as uttered by captive male chimpanzees at U.S.A. Lion Country Safari in Florida and at the North Carolina Zoological Park. A proper pant-hoot has four sections: an introduction with “at least one long, unmodulated, low-pitched element”; the buildup, with fast, short, inhaled and exhaled sounds (going up in pitch is an option here); the climax, with at least one long scream; and the letdown, which is much like the buildup.

  The Florida and North Carolina chimps showed definite differences. While the overall sequence length was the same, they emphasized different parts of the call. Moreover, the chimpanzees at Lion Country Safari often added tasteful Bronx cheers to their pant-hoots. This was due to the artistic influence of NL, a 30-year-old male who had been at Lion Country for 20 years. While chimpanzees in both colonies already made Bronx cheers when they were frustrated, only at Lion Country did they use them to adorn pant-hoots. When NL arrived as a 10-year-old, he had already mastered the cheer, and apparently it was his idea to use it in pant-hoots.

  Killer whales have distinct dialects, but what’s really unusual is that different pods in the same waters can have different dialects. Sometimes pods gather in larger groups with other killer whales in the population, and having your own pod-specific calls may help when it’s time to break up and go home with your own folks.

  Why don’t you lose that accent?

  What use are dialects? For one thing, in courting birds, they may signal “I’m from around here and I know the ropes.” The local boy may know the terrain better, and he may be genetically adapted for local conditions, as witness the fact that he has survived.

  Crows, noted for cawing, also sing. Theirs is a long and motley song, adorned with clicks, gurgles, rattles, coos, and other sounds that please them.* Scientist Eleanor Brown, who was clearly captivated by crows, writes that their song is “not often heard in the wild due to the wariness of this persecuted species.” So diverse are the elements of crow song that some ornithologists have compared it to subsong, but Brown considers it to be crystallized song of extraordinary variety. Brown suggests that crows imitate each other to come up with a group song, strengthening their bonds.

  Brown raised crows in outdoor aviaries and carefully analyzed their remarks. Under “harmonic rattle,” for example, she included the “rolling coo,” the “rattle ow’wa,” and the “short wow hoo.” Under “caw” we find the “ark,” the “wok,” the “kek,” the “haa,” and more. Although the vast array of “coos” is charming, my favorite vocalization is the “harsh ahah.”

  Sometimes the crows duetted: RU and G would perch only a few inches apart, “uttering the same sounds and performing the same movements in almost perfect synchrony.”

  When the crows were a year and a half old, Brown introduced the crow J, who was the same age, by putting her in an aviary adjacent to RU and G. J changed her song elements to match those sung by RU and G. Her “coos” were much higher: she lowered them. Her “hoo” contained longer notes: she shortened them. She pronounced “hwa” as if it were “hoo-wa”: she compressed it into “hwa.” This was not an instant process, but at the end of two and a half months J sounded like RU and G. The more she sounded like them, the more they liked her. “Colloquially speaking, song may be the ‘social grease’…which keeps daily life running smoothly.”

  Music appreciation

  Clarence, a house sparrow raised from infancy by Clare Kipps, did not grow up with other sparrows. Instead, he listened as Kipps played the piano, perching on her shoulder and pinching her neck at the exciting parts. He particularly liked anything resembling a trill, and treble scales played fast.

  Clarence was born during the London blitz. Refugees living with Kipps reported that he was singing while she was out. Since she knew house sparrows do not sing, Kipps thought they had heard birds outside and mistaken them for Clarence. But while she was running water one day, she heard Clarence in the other room. “It began with twitterings; then there was a little turn, an attempt at melodic outline, a high note (far above the vocal register of a sparrow) and then—wonder of wonders!—a little trill.”

  Once he had perfected his art, he was delighted to sing for Kipps and for visitors. He had composed two songs, each in the key of F major. Kipps suspected that Chopin’s Berceuse was the inspiration for his trills. The first song “began with the usual sparrow-chirpings, though less harsh in tone than those that sometimes weary us with their monotony in the early morning, and descended by a perfect fourth from tonic to dominant,” Kipps wrote. “This interval was followed by a perfect fifth descending from G to C; and these two were repeated and ornamented with mordents or (sometimes) with four-note trills. Then followed a rapid triplet leading back to the tonic and repeated indefinitely.”

  The second, rapturous song included two eight-note trills until Clarence was five, when he elected to replace the second trill with “a harsh croaking noise that sounded as if he were clearing his throat, but of which he seemed inordinately proud.”

  Clarence’s songs were curiously unprecedented. Looking in three bird guides, I read that the song of the house sparrow is “a long series of monotonous chirps,” a mixture of “various twitters and chirps, nervous and sometimes garbled; certainly anything but musical,” and “a monotonous series of nearly identical chirps.” House sparrow buff D. Summers-Smith wrote that at times house sparrows string chirps together to form “a rudimentary song.” Summers-Smith also wrote that a few of the captive sparrows he raised also developed something of a song, “a sustained, rambling warbling…built up of the adult chirrup notes but much more musical than normally associated with the house sparrow,” which they sang briefly as teenagers. He also heard such songs occasionally from wild birds, which suggests that most house sparrows perform below potential. Of Clarence, Kipps wrote, “His artistry was not impeccable, but sparrows are not a musical family, and his performance at its best was an achievement for one of his species.”

  Hummingbirds

  Hummingbird songs are high and thin, and people seldom notice them. That’s okay, they weren’t talking to you.

  The late Luis Baptista and Karl-Ludwig Schuchmann confirmed earlier suspicions that vocal learning in birds is not a monopoly of the powerful passerine-psittacine cartel, but is also found in the hummingbirds. In particular, Anna’s hummingbirds living on Guadalupe Island in Mexico sing very differently from mainland California birds.

  Baptista and Schuchmann raised some baby hummingbirds where they couldn’t hear adult song. A male Anna’s hummingbird who was raised alone sang a monotonous song devoid of trills and vibratos, but occasionally interrupted by unorthodox bursts of buzzy chatter.

  Since hummingbirds are raised by single mothers, males can’t learn from their fathers. It is thought that they learn obliquely, listening to unrelated males. The song of the hummingbird raised alone was similar to the song Anna’s hummingbirds sing on Guadalupe Island, suggesting that the island was colonized by hummingbirds among whom the male or males hadn’t learned songs yet. They founded a dy
nasty that never got to hear good music and passed along their pitiful tunes, which Baptista called “baby talk.”

  Kathryn Rusch and Millicent Ficken followed blue-throated hummingbirds in southeastern Arizona to see if they are learners too. Sure enough, blue-throats in the Chiricahua Mountains sing parts of their delicate “whisper song” differently from blue-throats in the Huachucas, suggesting a learned component. They discovered that female blue-throats sing in the breeding season. After she has single-handedly built an adorable nest, using spider’s silk, a female blue-throat goes looking for a male. She finds him perched and singing, and, if she likes him, perches next to him and sings her own whisper song. They spend a day or several days together, whispering, and then separate. She raises the twins alone.

  Cetaceans

  Some cetaceans have ears specialized for very high frequencies. Dolphins who live in often murky coastal waters and ascend rivers utter almost nothing but ultrasonic clicks. Hector’s dolphins, for instance, are chubby little spotted dolphins who live in New Zealand’s coastal waters, including harbors and river mouths. Since they are social creatures who love to gather in groups, and click like mad when they do so, it’s guessed that they are using ultrasonics not just to find their way about and find food but also to communicate.

  Bats

  Evening bat mothers can tell their pups’ calls from the calls of the other pups in the colony, and they learn this very quickly. Within a day, the pups are left in nursery crèches of up to 30 pups, while their mothers go out to forage. Mexican free-tailed bats pick their pups out by voice, in crèches that contain millions of pups. It was once assumed that no mother could locate her child in such a mob and that mothers just landed in the crèche and suckled a random pup, but it’s not true. The mother flies to the general area where she last saw the kid, which only helps a little, since the pups are virtually shoulder to shoulder, up to 5,000 of them in a square meter, each cuter than the one before. She searches the area, calling. All the pups scream, “I’m hungry!” and by voice, backed up by smell, the mother picks out her own darling.

  Leaf-nosed bats live in small groups with up to five females and one male. The males don’t take care of the pups, but if the pups are removed from a flight cage and experimenters play tapes of a pup crying, males will fly to the mother of the pup and poke and screech until she goes over to the loudspeaker. (Mothers seem to be better than the males at telling the difference between a tape and the real thing.) The males always knew which mother was associated with which pup.

  What do I get for my dues?

  The female greater spear-nosed bat gives a loud screech call at foraging sites and when she is leaving on a foraging trip in the tropical rain forest. In the evening, hundreds of bats pour out of a cave, and so a distinctive call can help the group stay together when everyone around them is flapping and screeching. Female bats forage in groups of 8 to 40 regulars (each group includes one male bat), and the screeches seem to help them gather and stay in touch when they are winging through the forest. Janette Wenrick Boughman investigated whether they did this by recognizing the voices of individuals, or whether they had a group version of the screech call. It seems that group members all adopt the same screech call, to the point that “individuals are statistically indistinguishable”(as if they fly around screaming “Crips! Crips!” Or “Alpha Chi! Alpha Chi!”). Boughman transferred captive bats between groups, and found that the transferred bats change their calls to match their group.

  Greater spear-nosed bats do not lead a simple life of jinking about grabbing insects on the wing, like some bats. Instead they eat a huge array of plant and animal foods scattered through the forest. Many foods occur in clusters, such as a flowering tree or a hatch of winged termites. It’s useful for one group to be able to exclude everyone who’s not in their group, which is easy to tell because they don’t know the password. “They seem to chase them off,” says Boughman. “There’s lots of calling and lots of really fast flying with one hot on the tail of the other.”

  A young bat is fed by its mother for a few months. Then, when it’s weaned, it hangs out with other teenagers in the cave and learns to find food by following older bats. After a while, young females try to join a group. Group members aren’t related, and Boughman has seen sisters join different groups. It takes between one and five months for a new girl to master the screech call of her group.

  Not only are greater spear-nosed bat screech calls audible to the human ear, but it’s gratifying to know that it is, barely, possible to tell the group calls apart, “if your ear’s well trained and you listen to a million of them.”

  Mimicry

  Clearly a parrot who says “How are you?” is not replicating an innate template. It has long puzzled ornithologists that many birds which mimic impressively in captivity aren’t known to mimic in the wild. Why should they have this remarkable ability which only manifests itself in this rare situation? Perhaps they do mimic in the wild, but not for our benefit. Listening to a four-minute tape of two wild African grey parrots vocalizing in a tree on the bank of a river in Zaire, Claude Chappuis noticed some motifs that resembled mimicry. Further analysis confirmed that the parrots (they couldn’t tell if it was one or both) seemed to be mimicking the red-tailed ant thrush, Lühder’s bush-shrike, the brown-throated wattle-eye, the western black-headed oriole, the bristle-nosed barbet, and a species of epauletted fruit bat.

  Wild parrots are not usually so cooperative with people taping their chitchat. The authors of a paper analyzing this recording write that the fact that there were two parrots vocalizing for a long time without other birds present suggests “a song or duet of socio-sexual significance.” Perhaps mimicry occurs in uncommon situations such as pair formation.

  Ravens

  In Mind of the Raven, Bernd Heinrich cites several examples of mimicry in captive ravens (one that imitates static on a portable radio and one that revs its motorcycle constantly) but also passes on an interesting incident of mimicry by a wild raven.

  Biologist David Barash, studying marmots in Olympic National Park, kept hearing a countdown followed by an explosion: “Three, two one, bccccchhh.” After hearing it several times in a row, Barash called out “Who’s there?” but got no reply. Eventually he discovered that the sound was coming from a raven seated on a nearby snag. The previous week, park rangers had set off explosions for avalanche control, and the raven had heard and added this to his repertoire. Later in the season, ravens who were in the habit of perching on top of self-flushing urinals in a picnic area added the musical sound of flushing to their rhapsody.

  Starlings

  Starlings are intimidatingly vociferous birds who include mimicry among their accomplishments. This is obvious in captive birds like Arnold, raised by Margarete Sigl Corbo, who progressed from saying “Arnold” in every possible tone on every possible occasion to imitating Corbo whistling “Mary Had a Little Lamb” and Beethoven’s Fifth to quoting small boys’ “See you soon, baboon.” He used this last phrase appropriately when people left the room.

  Lyrebirds

  The superb lyrebird of Australia is a multitalented creature who mimics brilliantly and in the case of the male, also sings, builds a mound to display on (a display which some call dancing), and grows ornate tail feathers. Young males initially learn from adult males, and later incorporate mimicry of other species.

  In the 1940s, some lyrebirds were introduced from Australia into Tasmania. Soon these lyrebirds imitated a Tasmanian bird, the green rosella. Forty years later, the population still imitated whipbirds and pilotbirds, which are not found in Tasmania—their calls had been handed down from lyrebird to lyrebird.

  In 1969, park ranger Neville Fenton recorded a lyrebird in the New England National Park in New South Wales, with a very odd, flutelike song in his repertoire. Asking around, Fenton was eventually told that in the 1930s a flute player living on a nearby farm had a pet lyrebird to whom he played. The bird learned tunes from him and added them to his song.
Eventually the bird was released. Fenton sent the recording to a sound expert, Norman Robinson. Knowing that lyrebirds can sing two tunes at once, Robinson filtered the recording appropriately and discovered that the local lyrebirds were singing a combination of two tunes from the 1930s, “Mosquito Dance” and “The Keel Row”—modified, but recognizable.

  Bird. James Bird.

  The famous lyrebird James, who lived to be at least 20, was renowned for replying “Hullo, Boy” to Mrs. Wilkinson, a stately widow who greeted him every morning with “Hullo, Boy” when she saw him foraging in her garden. James was glorified in the 1940 book The Lore of the Lyrebird by Ambrose Pratt, which not only chronicled his feats and included a photograph of James and Mrs. Wilkinson gazing soulfully at each other, but exalted the lyrebird as “possessed of an extraordinary mentality,” “one of the most sedate and respectable of all the wild creatures known to man,” and with “an elementary conception of social virtue.” To arrive at this conclusion, Pratt posited that the superb lyrebird is monogamous (it isn’t), that father and mother care for the young for five years (the mother tends it for one year), and that if they lose their mates, the females withdraw to “some deep recess of the jungle and remain hidden until they die of loneliness or grief” (they don’t). When lone males were seen, Pratt and his informants identified them as “widowers unwilling to remarry” (although he also says that “their demeanour presented…many aspects delicately suggestive of abnormality”—these are indeed complex birds). Pratt correctly noted that lyrebirds are territorial, although he thought that pairs owned property together, a further virtue.