Pompadours in the Palms

A rare bird’s elaborate mating habits help a tropical tree disperse its seeds.

umbrellabird

Male long-wattled umbrellabird puffs, fluffs, preens, and generally shows off for the benefit 
of any females passing the lek.

Murray Cooper

A full-grown chapil palm tree can reach 110 feet tall, its corona of forty-foot fronds stretching skyward above the surrounding canopy. Competition for space and light can be intense among rain forest trees, and every mature, fruit-producing chapil that towers overhead had countless less-fortunate siblings that perished during the long journey from seed to adult. But what determines the winners and losers in that lottery? In the case of the chapil, part of the answer may lie in the social behavior of a curious endangered species known as the long-wattled umbrellabird.

The chapil (Oenocarpus bataua) is widely distributed—and widely consumed—throughout the South American tropics. Mammals such as tapirs and peccaries rely on the palm’s date-size purple-black fruits for food. Indigenous people use the fruits for medicine, food, and to make a thick, rich, nutty-tasting beverage. Birds that feast upon the chapil’s protein-rich fruits and seeds include some of the Amazon rain forest’s biggest and most brightly colored species, such as macaws and toucans.

But on the other side of the Andes from the Amazon Basin the chapil palm serves the long-wattled umbrellabird—perhaps its most unusual avian patron—and benefits in return. There lies a distinct biogeographic zone called the Chocó, which extends down the mountains’ western flank to the coast in Colombia and Ecuador. That zone is characterized by rain forests even more humid than those of the Amazon, and harbors a distinctive and largely endemic flora and fauna. Thomas B. Smith, a biologist at the University of California, Los Angeles, and I have been studying long-wattled umbrellabirds and other endangered species in the Ecuadorian Chocó for several years. We initiated a conservation program that provides training, education, and sustainable alternatives to locals and Ecuadorian university biology students who assist in our research.

In our neck of the Chocó, the long-wattled umbrellabird (Cephalopterus penduliger) lays claim to the title of best-dressed dinner guest at fruit-bearing chapils. It is a large, charismatic, midnight-black bird, with a maximum wingspan of about two feet. Males have long crest feathers that, depending on their mood, they can retract like slicked-back pompadours (cool, relaxed) or expand to completely cover their heads (amorous, aroused). With his crest retracted, a male looks like Elvis on a bad hair day; with it expanded, he looks like Liberace on steroids. The crest accounts for the “umbrellabird” part of the name. Every male also has a thin, feather-covered flap of skin known as a wattle that hangs from his neck down past his tail. About eighteen inches long, the wattle looks rather like the ruffle on a tuxedo shirt, but functions more like a gold chain in the sexual lexicon of the species. Females are smaller than males and much more restrained in their appearance. Ecuadorians call the bird the pajaro toro, meaning bull-bird, because the male’s song resembles nothing so much as a lost bovine mooing in the forest. The calls travel more than half a mile, to attract females.

In spite of its outlandish appearance and trademark calls, not much is known about the long-wattled umbrellabird. It’s not an easy bird to see in the dark foliage; few birders and even fewer biologists have spotted it. It relies on pristine Chocó forests—habitat that is threatened by rampant deforestation. When the forest disappears, the umbrellabird is never far behind. Today it is in danger of extinction, its population having declined by at least 30 percent in the past decade—to less than 10,000 birds.

The loss of the umbrellabird would be a shame, of course, and particularly so for the chapil trees of the Chocó. My research shows that the chapils depend upon those flying fashionistas to disperse their seeds throughout the forest. At first glance, that service may seem trivial. But in fact, the importance to a rain forest tree of its seeds being carried to a favorable location cannot be overstated. Transportation away from the parent tree is key to a seed’s chances of survival to adulthood. Other birds and mammals eat chapil fruits, but in the Chocó nothing seems to eat more of them than long-wattled umbrellabirds, which flock to a fruiting tree and remain in the area for hours. When an umbrellabird feels peckish, it approaches one of the bundles of fruits that hang off the tree like horses’ tails, and hovers in front of it like some Daliesque hummingbird. Finally the umbrellabird plucks a plump morsel, swallows it whole, and returns to its perch to digest.

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