The Thing with Feathers (28 page)

wandering hearts

THE TRICKY QUESTION OF ALBATROSS LOVE

T
he romantic life of an albatross is a sweeping kind of romance, the dreamy feeling that all horizons open to an unlimited universe where anything is possible, given sufficient time and space. Albatrosses exist so close to infinity that on a windy day and in the right state of mind, far from the sight of land, the casual observer may be forgiven for forgetting that these are earthly creatures. What would it be like to drift on a pair of six-foot wings, pushed by the breeze, beyond the last vestiges of mundane life?

There’s something spiritual about albatrosses. With 95 percent of their lifetime spent over the open ocean, they live so much differently from how we do—from how most creatures on the planet do, actually—that it’s hard to conceive of these birds even breathing the same air, which may be why their lifestyle seems so romantic. I have watched people break down and cry upon visiting an albatross colony on a far-flung island, caught off guard, sinking to their knees as if on a religious pilgrimage. Sparrows don’t exactly elicit the same response.

Everything you’ve ever heard about albatrosses is probably true, and then some. We always suspected that they cover vast distances, but never imagined just how far until scientists began attaching global-positioning-system tags to individual birds in the 1980s.

The numbers are staggering. A gray-headed albatross was recently recorded circling the entire Southern Ocean, all the way around Antarctica, in forty-two days, and it kept sailing east with the wind at its tail, completing several round-the-world circuits in the following year. Laysan albatrosses nesting
on tropical Pacific islands routinely glide 2,000 miles up to Alaska and back just to grab a quick snack for their hungry chicks. Wandering albatrosses, with the largest wingspan of any flying bird—nearly twelve feet from tip to tip—may log several hundred miles per day, even resting on the wing. Circumstantial evidence suggests that they can shut off half their brain at a time, catching sleep at 40 miles per hour. Because of a special shoulder-locking tendon, albatrosses don’t use energy to hold their wings out; their resting heart rate is probably
lower
in flight than it is when they are sitting on the ground. If you multiply the percentage of each day a wandering albatross spends in the air by its average cruising speed and expected lifetime, a typical adult wanderer will have traveled, conservatively, 4
million
miles in its life—the equivalent of eight round-trips to the moon, more than any other animal on earth, more than any single car humans have ever constructed. Wanderer indeed.

The life of a restless spirit isn’t always as romantic as it sounds, however, as any weary traveler can attest. When you’re always on the wing, covering a hundred thousand miles a year, it’s difficult to sit still long enough to find the daily, earthly romance of a soul mate. One might then logically assume that albatrosses, the rolling stones of the bird world, have made some necessary sacrifices in their love lives. Not so. These globe-trotters, who mate for life and are incredibly faithful to their partners, just might have the most intense love affairs of any animal on our planet. That’s what makes these birds so emotionally captivating up close. To see what real devotion is like, you need to spend some quality time with an albatross.

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BIOLOGISTS DON’T TALK MUCH
about love—the word has too many meanings, is too unscientific for academic use. When
discussing love between animals, they tend to use more clinical terms, such as “pair bond” and “monogamous relationship,” generally implying attraction without the squishy overtones. There is no way to physically measure love, which is part of what makes it so mysterious and inspiring.

Still, we know a few things about how love works, especially in humans. When two people fall in love, their brains act in predictable, somewhat prosaic ways. To be precise, you never love with all your heart—in fact, you love with your ventral tegmental area and caudate nucleus, nestled deep within your skull where basic drives, like hunger and thirst, are processed. One recent study found that college kids who described themselves as “madly in love” were producing high levels of dopamine, the same chemical released when the brain reacts to cocaine (which gives that fluttering-heart sensation). No wonder lovebirds sometimes do crazy things; they’re all high as kites.

Fortunately, those initial effects don’t last forever. Levels of dopamine and other chemicals associated with romantic attraction—including pheromones, serotonin, and nerve growth factor protein—seem to drop back to normal within one to three years. Relationships invariably settle down after the first puppy-dog stage; the spark doesn’t necessarily go out, but the brain reels itself back into sobriety.

The same flush of chemicals is likely present, at least to some degree, in many animals. But it doesn’t tell the whole story. Love is much more than getting high. If that were all, then we’d be running around searching for the next hit—and, with a few exceptions, that’s not generally how it works for us. Most people settle into long-term relationships, cozying up with one dedicated partner indefinitely. Biologists explain this as attachment, theorizing that couples stick together for essentially the
same reasons that a kid sticks with its mother: The arrangement benefits both parties. Initial lust glues people together and then dries in place. But attachment is harder to measure than lust because it doesn’t leave as many traces of chemical activity and can be hard to predict.

The saying “opposites attract” isn’t really true when it comes to human relationships. We do often seek out romantic partners with contrasting genes for immune systems, even though we aren’t consciously aware of each other’s genetic makeup—a tendency that has also been shown in other vertebrates, and likely gives our kids better immunity from diseases. But generally, our ideal partner is a self-image with opposite gender: same social status, same health, same age, et cetera. The more similar you are to your partner, the more likely you are to develop a long-term attachment past the initial head-over-heels stage. The more differences between you, the more cracks will appear over time.

We know instinctively what it feels like to be in a long-term relationship, but it’s hard to say whether other animals feel the same way. Do albatrosses get high when they meet a potential mate? What goes through their minds twenty years later, when they’re still nesting with the same partner? Do they work through the same stages of love? Some would argue that any expression of emotion in animals is dangerously close to anthropomorphization, but anyone who’s ever had a pet, or worked intensively with a few individual birds over a long period of time, can speak to a variety of different moods. Why not outright love?

Personally, I think albatrosses feel love even more intensely than we do, and available evidence seems to back me up. No matter what category of affection you study, albatrosses beat us every time.

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ONLY ABOUT 3 PERCENT
of the world’s 5,000 mammal species are considered socially monogamous. Besides humans, the list includes wolves, beavers, and a surprisingly amorous prairie vole. However, at least 90 percent of all birds pick dedicated mates at some point in their lives. (A few other animals form long-term pair bonds, including the parasitic worm that prefers to copulate with its special lover deep inside the human liver.) Before you jump to rosy conclusions about birds mating for life, though, be warned that appearances are deceptive.

Monogamy among birds isn’t a yes-or-no proposition. Relationship strategies span the full range between total devotion and complete promiscuity, and most birds fall somewhere in the middle. For many, loyalty is an arrangement of convenience. In hummingbirds, the bond lasts just long enough to copulate, for perhaps a couple of seconds. Then females buzz off to build a nest and raise chicks on their own while the males sip flower nectar all summer. Most songbirds have summer flings, sticking together barely long enough to raise a brood before going their separate ways. This tends to work out fine because most songbirds don’t live very long; it doesn’t make sense to commit to a long-term relationship if your partner will probably drop dead within the next year. Accordingly, birds that traditionally mate for life tend to be larger and longer-lived: geese, swans, cranes, owls, parrots, eagles, gulls, penguins . . . and albatrosses.

Even the most dedicated bird couples often sneak around behind each other’s backs. Biologists thought for many years that if two birds paired off with each other, they could be defined as monogamous—one male, one female, and their children—but modern DNA testing has shown that this is
rarely the case. Most birds do form steady pairs that work together, as it’s difficult for single parents to raise young alone, but the offspring from those pairs often have unexpected fathers. In other words, mother birds routinely go for surreptitious quickies.

Some supposedly monogamous birds are more promiscuous than others. The world’s loosest bird may be the saltmarsh sparrow, a tiny, mousy inhabitant of muddy coastal wetlands in the eastern United States. One study found that more than 95 percent of all nests included eggs fertilized by other fathers, that the average nest included DNA from 2.5 males, and that the chance of any two nestmates having the same father was a mere 23 percent. Even so, the little sparrows paired off and faithfully raised their broods as if nothing were happening on the side; the only clue to their dalliances was the differing DNA in each egg. Few birds can rival that amount of cheating (though the vasa parrot in Madagascar and the superb fairy-wren in Australia are close), but almost all birds sleep around a bit. The idea of faithfulness among bird couples is mostly a romantic delusion.

Not that female birds don’t at least try to stay faithful. A significant percentage of extra-pair copulations in otherwise monogamous birds may be forced by wandering males without the female’s consent. Female ducks of several species have occasionally been observed drowning while attempting to evade the advances of aggressive wandering males. But many females sneak out willingly to copulate with males that are not their main partner, sometimes on neighboring territories, with the same result: A father may unknowingly raise chicks that aren’t his. Even swans and doves, traditionally the shining examples of true love in the animal kingdom, don’t always stay faithful, although they tend to score at the low end of the promiscuity scale. Strict monogamy comes at a price. To be sure of
fathering their own chicks, male mourning doves must always stay close to their females and viciously attack intruders, belying their peaceable reputation.

Divorce rates in birds with long-term partners—the percentage of pairs that break up before either bird dies—are instructive. The proportion of divorces varies wildly among birds that are said to mate for life. Flamingos, for instance, are terrible at keeping commitments, with a chart-topping divorce rate of 99 percent. Tropical birds aren’t the only adventurers; king penguins are likewise fickle, with a divorce rate near 80 percent (unusually high among penguins, which generally stay together for many years). By contrast, only 5 or 10 percent of swans divorce, and some species of ravens have even lower divorce rates.

Bird divorce is quite well studied, and there are competing hypotheses for why two birds would get together, spend a few years in a relationship, and then go their separate ways. One theory, called the incompatibility hypothesis, argues that some individuals are just not meant for each other even though they might play well with others. Another popular hypothesis says that some slacker birds won’t be productive no matter whom they’re paired with; mates of these lowlifes should be motivated to leave at the first opportunity.

The latter seems to be true in at least some cases. Female blue tits in Europe generally improve their breeding success after they dump one male for another of better social status, indicating that some males are better than others (dumped males, accordingly, experience lower breeding success). But leaving can also be risky because, without an immediate plan, a sudden divorce puts a bird back into the singles scene, and another mate can be hard to find. One study of gulls discovered that fully a third of female divorcées never nested again, even though some lived another ten years. Sometimes, mates won’t
leave without a fight; female skuas have been known to kill one another outright in battles over desirable males. You’d think that the males would step in to defend their mates under attack, but they take no part in these disputes—cool and calculating, they know that the strongest female will win. Which makes you wonder: What kind of love lets you stand by and watch your mate be killed, then happily pair up with her murderer as if nothing has happened?

Current predictions estimate that about 40 percent of new human marriages in the U.S. will end in divorce, which places us on about the same romantic level as the Nazca booby, a type of seabird known for, among other things, routinely slaughtering its own siblings inside the nest. It’s hard to say how many human couples raise kids with the DNA of only one parent, but it happens. Like birds, we are socially monogamous but don’t stay faithful all the time.