Marital harmony
Ngaio, an inexperienced young female black robin, paired up with Crunch, an inexperienced male. Crunch sensed that when you court a girl, you should feed her dainty insect items, but it took Ngaio a month to accept them. Perhaps this was because Crunch was rather aggressive, chasing Ngaio when she was feeding and even when she was trying to mate with him. And perhaps this is why Ngaio dumped him for Mertie the next year.
A young male named Pani had a different problem: he’d start to feed his mate, Baby Blue, and then grab the bug back.* Black robins are a species in which both male and female feed the young, and the male feeds the female while she is incubating the eggs, but males often take a while to figure this out, leaving their brides to feed the whole family themselves. Pani did such a poor job of feeding Baby Blue when she was sitting on their eggs that social services/researchers had to step in and feed her.
Lovebirds mate for life, and they’re decisive. They fall in love just like that. “It takes no more than a few hours to establish lifelong pairs.” But it takes a lot longer to get things working smoothly. At the beginning they’re awkward. They misunderstand each other. They take offense. Often a male makes “many mistakes” in attempting to mate, and is “threatened and thwarted” by the female. (For one thing, he needs to notice whether her head plumage is fluffed up—a good sign—or sleeked down—a bad bad sign.) By the time they’ve raised a few broods they understand each other better, fight less, and mate more often. The male is less often seen showing frustration by squeak-twittering, displacement scratching, and switch-sidling.
Mating with your mate
Sex is where the next generation comes from, so I feel obliged to point out that learning is involved here, too. Animals often display a strong, not to say profound, interest in sex along with complete confusion about what it actually is.
Researchers studying endangered black-footed ferrets note that while an experienced male ferret needs little direction from a mate and in most cases “simply grabs the female by the neck and mounts,” things may not be so simple for beginners. A young male ferret without experience is likely to hang back, and a female may encourage him with “soliciting” behavior, approaching in a low crouch with her head and neck extended toward him. She will pause before moving forward a little more. She may chuckle invitingly. Once she gets close she may put her head under his chin. (Hint, hint.) If he doesn’t react, she may rub against him. (Yes, you.) “In one extreme case, an older female, having exhausted all the procedural niceties without response from an inexperienced male, finally seized him by the neck, pulled him into the nest box, and crawled beneath him. Her efforts were finally successful in spurring the young male into action.”
Tigers need to learn about mating, and inexperienced tigers may have awkward moments. “If you have two tigers that have never mated before, they have a pretty difficult time,” says tiger expert Ron Tilson. When tigers mate, the male seizes the female by the back of the neck. “It’s a huge irritation to the female,” and when sex is over the female usually turns and belts the male with a savage clout. Males learn to anticipate this and jump back, but it can be a shock for an inexperienced young male tiger who thought things were going rather well up until then. “He doesn’t expect this to happen, and he really gets clobbered, and he gets very angry,” Tilson explains. He contrasts this with one older male who knows what’s coming and at the right moment leaps so high that the female’s swat misses him altogether.
Breeding captive tigers seems to be a learning experience for zookeepers as well as tigers. Female tigers in estrus are extremely fierce. “When a female is in the wild she needs to be able to handle these very aggressive males. She has to be pretty tough to deal with them. The male has to hang out with her for about three days till she’s ready to ovulate, and during these three days the male is trying to copulate with her and she doesn’t want to, and there is an extraordinary amount of growling—it scares the devil out of keepers.” Whenever Tilson (a coordinator of the tiger Species Survival Plan) recommends that a tiger breeding take place at a zoo where the process is unfamiliar, he knows that eventually he’ll get a horrified phone call: “‘Gee, Ron, we put them in together—we thought she was ready, she was calling and rolling and rubbing against the walls—and my God, there was a big fight!” Tilson tells them to be brave and put the tigers back together to work things out.
You may also have been wondering about the sex lives of chimpanzees who’ve been raised in boxes for the first three years of their lives. Well, it’s a problem. If for whatever reason you took chimpanzees from their mothers within 12 hours of birth and reared them “in closed boxes in isolation from humans and other chimpanzees,” you might, years down the line, wonder about their capacity for normal sexual behavior. (This is old research. They don’t do this to chimpanzees anymore.)
It turns out that this kind of upbringing handicaps chimpanzees sexually as well as making them “withdrawn, fearful, socially eccentric animals.” Male chimps raised this way and then put in a small cage with a female chimpanzee were unable to make headway with girls their own age, whether the females were raised in a box or wild-born. Only with older, “sophisticated,” wild-born females did anything happen. “Copulations were the result of the skill and persistence of the females, who frequently effected intromission by trapping the male in a corner and backing onto the erect penis,” the authors note, impressed.
Box-reared females were not active participants in sex, either, but after a month or two allowed experienced males to mate with them. Things went somewhat better for the box-reared chimpanzees when they were placed in a group with other chimpanzees who had slightly more normal backgrounds, and some of them mated regularly, though the observers scorned their technique (“brief, perfunctory”). Of the box-reared females, only one out of seven avoided sex entirely. Of the five males, one was not tested, three “exhibited sex behavior which, if not completely normal, was successful to the extent that intromission was accomplished,” and the fifth, while avoiding other chimpanzees, had occasional liaisons with a 55-gallon drum.
Wait, so that’s where babies come from?
Before birds can cherish their nestlings, they must cherish their eggs. Eggs are demanding and need to be kept warm almost constantly. They need to be humid, but not too humid. They need to be turned daily. Birds generally have strong innate wishes to tend their eggs, but that in itself can lead to problems.
Inexperienced California condor parents must work out a routine. Condors are egalitarian, and mother and father take turns incubating the egg while the other one goes out for some refreshing carrion. It’s not a sacrifice for the parent who sits on the egg. Condors like to do it. It’s satisfying. Sometimes when the other parent arrives to take over, the first parent isn’t ready to leave.
CCM and CCF, wild condors observed in the 1980s, had not worked this out. CCM hated to leave his egg. He would sit on it for as long as 10 days and when CCF showed up, he’d attack her. It sometimes took CCF a couple of days before CCM—who had to have been hungry by then—would let her take a turn. Their fights were so prolonged that in 1983 concerned condor watchers decided to seize the egg if the next fight lasted for more than three hours, because they worried that while CCM was busy kicking CCF out of the nest cave, the egg was getting cool. The next day, a grieved condor watcher recorded “senseless hysteria” and domestic violence at the residence, and authorities took the egg after four hours. (It hatched in captivity.) They replaced it with a lovable dummy egg.
CCF, who had always been “submissive toward the male,” and who only got to take a turn by being meekly persistent, eventually got fed up. One day she arrived to incubate the egg, CCM got ugly, and she bit him. She bit him until he let her sit on the egg. After that, any time he refused to yield, she bit him, and he behaved himself for the rest of the season.
In later years CCM died, and CCF was trapped for captive breeding. She was so savage to all males that biologists did a blood test, wondering if su
ch an aggressive creature could be female. “It is tempting to attribute the aggressiveness of this bird to her history of coping with her hyperaggressive former mate,” write Noel and Helen Snyder. It wasn’t until 1995 that CCF met a guy she could live with and resumed breeding.
Picking the right neighborhood
Even when birds know how to make a nest, they may need to learn about selecting its location. Pinyon jays learn from experience about dangers to their nests. Researchers studying pinyon jays in ponderosa pine forests found that the principal perils came from predators and cold snaps in the weather. If a jay’s nest was in too shaded a position, and a cold snap came on, snow would remain on the nest and it would often be abandoned by the chilled parents. Nests in more open positions got more sun, but they were more apt to be robbed by crows or ravens, who cruise over the treetops looking for nests. Researcher John Marzluff looked at how male jays (the male selects the nest site) picked sites after a nest failure.
If a nest was preyed on, jays tended to build their next nest lower and in a more concealed spot. However, in two cases where jays built nests low down and had the nests robbed by cats, they then built nests near the treetops. If a nest failed due to cold, they tended to build the next one higher up. When jays successfully raised young, they built their next nest in a similar position.
Jays are long-lived and accumulate experience over the years. Young jays are more apt to make the mistake of choosing a lovely sunny nest site without worrying about the eating habits of the neighbors.
Marzluff suspects that in the past, jay nests were most likely to fail due to snowfall, but notes that the jays in this population have been subject to increasing predation as the raven population has boomed. The fact that pinyon jays can change their nesting practices quickly as their environment changes enhances their survival.
I like the look of natural wood
The Mauritius kestrel also changed its nesting practices, rather late in the game. This species was down to just four wild birds in 1972. Things didn’t look good. While the use of organochloride pesticides had a lot to do with its decline, the final insult was that some idiot had introduced macaques onto the island of Mauritius, and the macaques liked to climb trees, reach into kestrel nests, and eat kestrel eggs. Cats, which some fool had introduced, didn’t help, nor did mongooses.* Before the kestrel population plummeted, museum specimens had been collected. By looking at these specimens, ornithologist Stanley Temple was able to tell whether the bird had nested in a tree cavity or on a cliff. Kestrels who nested on cliffs had tail feathers worn down by the basalt. Apparently kestrels had mostly nested on cliffs until about 1900, when for some reason, they began nesting in tree cavities. They went on nesting in trees and providing macaque snacks as their population dwindled. In 1974, the last remaining pair thrilled well-wishers by nesting on a cliff and raising three chicks. Since that worked well, they went on nesting on the cliff, and their children, who had grown up on cliffs, also nested on cliffs.
Since then the population has been augmented by captive-bred birds, and macaque-proof nest boxes have been supplied. Pesticide bans were enacted. There are now hundreds of Mauritius kestrels.
Adoption
Among the various ways animals produce families, there are nonstandard options. There’s a surprising amount of willingness to raise other animals’ kids out there. Common eider ducks nesting in Manitoba frequently brood clutches of eggs that include the eggs of other eiders and then raise the resultant ducklings. One or two extra eggs or ducklings are no more trouble to these tolerant mothers. DNA testing has shown that some polar bears in the Canadian Arctic are raising cubs who aren’t their own. How this happens isn’t known, but some speculate that the mothers don’t know or don’t care whose cubs are whose. Since polar bears are solitary, this theory holds, they don’t need to distinguish their cubs as individuals. If there’s a cub around you, it must be your cub. But when gathering at bonanzas such as a whale carcass or a garbage dump, you might take the wrong cub home.
Wildlife rehabilitators Jan White and Cheryl Millham explain how to get a mother merganser (handsome fish-eating waterfowl) to adopt orphaned chicks. The ideal target is a merganser with chicks the same size as, or smaller than, the ones you want her to take. First take the orphans out and let them peep loudly to attract the attention of the mother. “Maneuver as close as you can to her and gently underhand toss the chick towards her,” they pleasingly advise. Then back off. With any luck, the mother merganser will call her chicks, the adoptees will rush toward her along with the others, and she will accept them as more of the gang, thus saving you many weeks of care during which the chicks would be gobbling 100 goldfish a day. (These are the smallest, “comet” size of goldfish. When the chicks are bigger you could trap minnows, and a mere 30 to 60 a day per chick should suffice.)
In Kenya, a crowned eaglet was brought to Simon Thomsett. The downy eaglet was about a month old and uninjured, but her home had apparently been destroyed by logging. Thomsett, knowing a bit about crowned eagles, and having “a high regard for their intelligence,” decided to see if he could place the young bird for adoption with a pair of wild eagles. They had nested earlier in the season in their territory along the Amboni River, but had abandoned the nest after two months when their egg didn’t hatch. Although five weeks had passed, Thomsett enlisted the aid of the park warden of Aberdare National Park, Phil Snyder, who ascended the forbidding nest tree, a task which took two and a half hours, and fooled around in the nest a little (he could walk in it—it was two meters across!) before hauling up the eaglet in a sack and leaving her there.
The next day the chick sat in the nest peeping of her hunger and solitude to any raptor that flew over. The male eagle who had nested there weeks before flew past doing a territorial display. “Suddenly he stopped the display and I felt sure he had seen the chick,” Thomsett reported. The next morning the male and his mate returned to the site. The female perched in an adjacent tree and peeped to the eaglet. The eaglet peeped back. The female eagle flew to the nest, where the chick bowed submissively. “Immediately the [female] showed signs of parental behavior.” Soon the male joined in. When Thomsett returned the next day the female was on the nest, the chick was snacking on a young antelope her new parents had brought her, and the male was off hunting for a family of three.
(It is very tempting to supply dialogue for the parent eagles. “Honey, remember our egg? It never hatched, did it?” “No, it didn’t.” “You’re sure?” “Of course I’m sure. I brooded that egg every day for two months, remember?” “Yes, that’s what I thought.” “Why do you ask?” “Well, I think there’s a baby in our nest.” “That’s ridiculous. We haven’t been back there in five weeks. How could there be a baby in our nest?” “I know, I know…. I think it’s hungry.”)
Does your mom think I’m cute?
During the reintroduction of wolves to Yellowstone National Park in the 1990s, a female called either Natasha or Number 9 was widowed shortly after giving birth to nine pups. When the male was shot, the pack fell apart, and there was no one to help her feed the puppies. So biologists recaptured the family and put them in a pen until the pups were less needy. When the pups were about three months old, a windstorm knocked a tree onto the pen, making a hole just large enough for two of the pups to get through. Biologists worried that either coyotes or a grizzly bear would kill the pups. Just then a hero arrived, Number 8, a young male wolf from another pack. (Actually, he had been noticing Number 9 for a while.) Now he ran the coyotes off and started regurgitating food for the pups. He hung around, protecting, feeding, and playing with the pups until the biologists finally let Number 9 and the rest of her children out. Sure enough, she had been admiring him too, and they became a pair.
Running away from home
Herring gull chicks who have lost one or both parents and are at risk of starving will try to get adopted. This is risky, since adult herring gulls frequently attack strange chicks, and may kill and even eat them. The
hungry little orphans get as close as they can to the nest where they hope to live, and crouch down. If the adult pecks at them, they creep even closer, since gulls have a reluctance to peck at chicks in their own nest. Usually, within a day or two the chick is adopted. White stork chicks in Spain sometimes join other stork families, but not because they are starving orphans. They are “greedy eldest chicks from the largest broods,” and by moving in with a stork family with younger chicks, they can be fed for a longer period before they are forced to earn their own way.
It’s a girl? What’s a girl?
Animals giving birth for the first time may have no idea what’s going on. Equine veterinarian Sarah McCarthy describes an eight-year-old mare named Merganser foaling for the first time. After the foal emerged, Merganser got up and walked away. The humans chased her, brought her back, and showed her the bay filly, to Merganser’s obvious delight—she just hadn’t realized there was a baby horse around until they showed her. One of McCarthy’s own horses, Holly, “wanted a foal very much,” as evidenced by her extreme interest in foals and her tender nickering when she saw them. (Nickering is a friendly sound made to foals as well as in other situations.) When Holly foaled for the first time, at age 12, she failed to grasp the implications of labor. After the delivery Holly lay in the straw of her stall, feeling sorry for herself and “calling for cold cloths.” McCarthy grabbed Holly’s head and brought it around to where she could see and smell her chestnut colt, Tristan. Holly was ecstatic—at last a foal of her own!—and began to nicker. When she had her next foal, she knew what to expect.
Dearie, a knowledgeable thoroughbred brood mare, had foaled 10 times. For her eleventh, she was sent to a veterinary clinic because of worries that she might have problems. She was in an outrageously advanced stage of pregnancy and staff were keeping an eye out for signs of labor. One staffer, checking on Dearie, lifted and peered under her tail—and Dearie began to nicker hopefully. (She foaled successfully, but not that very second.)
Becoming a Tiger: The Education of an Animal Child Page 34