by Howard Youth
Elephant, zebra, and wildebeest tails swished to the rhythm of clicking camera shutters. While my safari mates tore through film, my eyes drank in a three-foot-tall, pointy-headed fowl calmly walking among Ngorongoro Crater's drowsy game. For years, I'd read about African, European, Asian, and Australian bustards and longed to make one's acquaintance. Finally, I saw for myself what at first looked like a cross between an ostrich and a monitor lizard. Except for feathers, the kori bustard seemed reptilian, with piercing yellow eyes, thick long legs ending in tiny feet, a stiletto-like bill, and a long gray- and black-peppered neck.
Suddenly, the driver lurched our Land Rover forward, pursuing a black rhino that just crossed the dusty road. At that moment, I looked ahead and saw another bustard in the dirt ahead of us. As we bore down upon it, the huge bird skittered on lanky legs and laboriously flapped, slowly rising from the road. It barely cleared the Land Rover's roof before veering to safety on the straw—yellow plains.
Although dwarfed by elephants, kori bustards (Ardeotis kori) and Eurasia's great bustards (Otis tarda) are jumbos of the bird world. Males of each species weigh up to 33 pounds-about as much as two Thanksgiving turkeys-and share the flying-bird heavyweight title with only one other species: the mute swan (Cygnus olor). But bustards' champion status belies the fact that biologists are just learning the details of their flashy lives. And not a moment too soon. Bustards and people don't generally mix well. This bad chemistry leaves bustard populations reeling: Of the world's 25 bustard species, most are in decline, and many have disappeared from broad stretches of their former ranges. A few may soon go extinct.
Most bustards inhabit grasslands or dry bush country in Africa, where biologists believe the family got its start some 70 million years ago. Two species—the great and little bustards (Tetrax tetrax)—range from Europe eastward into Central Asia, three others haunt Asian steppes, while one slinks around Australia's Outback and a grassy bit of New Guinea. One of the most widespread, the houbara bustard (Chlamydotis undulata), lives from North Africa to Mongolia.
Over the millennia, bustards evolved into a diverse family best known by ornithologists for lavish and distinctive courtship displays. Dr. Suess could not have conjured up more off-the-wall rituals. Each breeding season, males flamboyantly compete for females' attention on traditional staging areas, or leks. Some species strut, some run, and others quake, flap, and puff out their plumage. Consider the houbara, a pheasant-sized bird native to fragile desert fringes. Males of this species run while puffing out shaggy white chest and crown feathers. With their heads buried in fluff, preoccupied competitors sometimes slam into things standing in their path. Male little bustards beep while jumping three feet above their grassy surroundings, while India's endangered lesser floricans (Sypheotides indica) reach greater heights. These endangered black and brown birds launch up to six feet high in a second, rattling their wings in a routine that males repeat more than 500 times daily during courtship.
Other bustards, including greats and koris, transform themselves into puffballs, flipping much of their plumage upside down in energetic fits of pomp. This past April, ten miles outside Spain's capital Madrid, I watched ten male great bustards blink on and off like lights from about a half-mile away across wheat and fallow fields. Through a spotting scope, I saw them twist their wings, tip their tails over their heads, swing their necks back and puff out their chests, exposing all white-feathered areas. Thick-necked and up to three times the size of females, these posturing males are "like a bunch of bodybuilders doing incredible displays—they're very contorted," says Nigel Collar, an ornithologist at the Britain-based conservation organization BirdLife International.
Although I couldn't see them, female bustards watched the exhibitionist males from nearby cover. These invisible spectators really run the show, quietly slipping onto leks of the few most dominant and showy males and copulating with them. Although many bustards' breeding habits remain poorly understood, five African species in the genus Eupodotis are likely monogamous; in the rest, like the great bustard, males usually mate with multiple females. After mating, females go off on their own to lay their eggs on a scantily covered but well-hidden patch of earth, while most males leave the area to feed in male-only flocks. After a month's incubation, great bustard chicks hatch and run after their mothers within a few hours. Hens cram protein-rich insects down the chicks' throats and youngsters tag along with them until the next spring, then strike out on their own.
Invisible Wanderers
Outside breeding season, many bustards lead nomadic lives, seeking plants and small animals wherever food supplies hold up against often—severe heat and drought. Most species eat their share of agricultural pests. Kori bustards, for example, frequent locust swarms, feasting upon African farmers' worst winged nightmares. A diet study published in 2000 in the British journal Ibis found that houbaras must each consume about 670 desert invertebrates daily to meet their energy needs. A sampling of the mixed bag taken by another species hints at bustards' opportunistic nature. Australian ornithologist Kate Fitzherbert describes the Australian bustard's (Ardeotis australis) diet as "a wide variety of insects, particularly grasshoppers, small vertebrates including native and introduced rodents, reptiles, and small birds, seeds, leaves and fruits, and also mollusks and centipedes."
Bustards' plant menu selections sometimes get them into trouble. For instance, sub-Saharan farmers consider the Arabian bustard (Ardeotis arabs) a pest because it nibbles acacia saplings planted for the extraction of gum arabic, an ingredient in pharmaceuticals and soft drinks. Europe's great and little bustards feed on alfalfa much of the year, and leaves of other legumes such as vetch and clover are also featured on bustard menus. But farmers often plant these crops to infuse nitrogen into their soil rather than for harvesting. Conservationists now encourage farmers to increase their legume acreage as a way to benefit the declining birds. By and large, bustards do farmers more good than harm, and they're rarely abundant enough to cause severe crop damage.
Despite the males' brash breeding displays, bustards spend much of their lives slinking unobtrusively through wide grassy or bushy spaces. Hidden in often remote habitats, many bustards long escaped biologists' attention. For example, nobody knows the courtship and mating rituals of three African species, the Nubian (Neotis nuba), Heuglin's (Neotis heuglinii), and little brown bustards (Eupodotis humilis). Huge gaps remain in what is known about more familiar species like the kori.
Last year, Smithsonian's National Zoological Park animal keeper Sara Hallager, who cares for the Zoo's burgeoning bustard flock [see "The Zoo's Bonus Bustards"], spent two weeks in Namibia. There, she and Tim Osborne, a retired Alaskan biologist now dedicated to bustard study, tried to unravel some of the kori bustard's best-kept secrets. "Amazingly, but true," says Hallager, "no one has studied these large, conspicuous birds to this extent in the wild before."
Hallager worked with Osborne to collect kori blood for DNA studies. "We wanted to compare the two subspecies of kori bustard to see how different or alike they really are," she says. One population, A. k. struthiunculus, lives in tropical East Africa and the other, A. k. kori, is found far to the south, mainly on grassy plains and in tree-dotted and scrubby savanna. Hallager and Osborne caught ten bustards by slowly guiding them into fine-meshed nets strung between scattered trees. Next, they drew blood samples and weighed and measured the birds before releasing them. Back in the United States, tests performed by the Zoo's Genetics Lab revealed substantial differences between the two subspecies' mitochondrial DNA. "This suggests that the two populations may indeed be separate species, although further testing may be necessary," says Hallager. If declared separate species, the two bustard populations would likely receive more attention from conservationists, who will need to take a careful look at plans to protect not one but two kori bustard species.
Osborne has also radiotracked Namibian kori bustards since 1997, fitting captured birds with lightweight radio tags attached by a harness. In the future, Osborne wants to monitor the birds via satellite because, he says, "We have never been able to find any juvenile males after our initial tagging. Their dispersal is beyond our limited radiotracking means." Osborne's work paints a different picture of a bird once assumed to stay put. "We now know that koris have similar movements to the great bustard, with some migrants, some residents, and some a mix of the two, depending on drought affecting insect abundance," he says.
For more than a decade, Juan Carlos Alonso, a biologist at Madrid's National Museum of Natural Sciences, and his colleagues have tracked Spain's great bustards, studying their biology, population demographics, and conservation needs. They debunked the myth that great bustards are sedentary. "Through marking and tracking them with radios, we have observed that they move up to 150 miles between breeding sites and summering and wintering sites," says Alonso. Without electronic spying equipment, the biologists would have remained in the dark about great bustards. "They really are horrible things to study," recalls Collar, who spent his months in Portugal cramped in a blind, sneezing from blowing pollen. "Just trying to figure out where the females are is amazingly difficult."
The Case of the Harried Houbara
Cryptically colored, shy, and often active only at night, dawn, or dusk, houbara bustards also give biologists headaches. Recent satellite-tracking work, however, revealed bizarre migration patterns in Asia's heavily hunted houbaras. In a recent article in BirdLife International's magazine World Birdwatch, Frederic Launay, an ornithologist at the United Arab Emirates' Environmental Research and Wildlife Department Agency in Abu Dhabi, reports that "…birds from the same brood and a female and her offspring don't migrate together, nor do they follow the same route, nor do they even winter at the same locality!" Wintering birds captured and tagged in the United Arab Emirates (UAE) flew to nesting areas in Kazakhstan, Uzbekistan, and China. Yet only one of these birds returned to the UAE to winter, and it was a Chinese bird that had tackled a round-trip journey of 7,400 miles-not bad for a chunky bird! The others turned up in Iran and Afghanistan.
"The main problem with bustards is the generally low priority accorded to the conservation and sustainable use of grasslands, steppes, and range lands throughout the world," says Paul Goriup, an ecologist who until last year was the chairman of the Bustard Specialist Group of the World Conservation Union. The houbara illustrates Goriup's point. Under bushes and amid grasses, houbaras find not only important plant foods and cover but also safe places to seek mates and form flocks outside breeding season. On their dusty, mostly open habitats, the most "lush" areas still might have less than 20 percent vegetative cover.
In a paper published in Ibis, biologists Yolanda Van Heezik and Philip J. Seddon found that houbaras breeding in Saudi Arabia's Harrat al-Harrah reserve-home to Saudi Arabia's last wild houbara breeding population-chose different habitats depending upon season and available vegetation. The biologists concluded that "reserves set aside for houbara bustards should be extensive, diverse, and largely free of livestock, human occupation, and its associated disturbances." Much of the houbaras' former Saudi Arabian habitat no longer fits the bill. Even the reserve might not protect many. The researchers concluded that only about 25 percent of the property is preferred houbara habitat, such as dry washes and lake beds, leading them to wonder if the birds still bred there because of reduced hunting and grazing pressure, rather than because the reserve was the best habitat.
Another part of the houbara's saga illustrates that while habitat loss is enemy number one, other threats often compound the birds' troubling situation. For instance, wealthy falconers from Middle Eastern countries travel across North Africa, Pakistan, and other places to set their raptors and rifles on Arabian, Nubian, and especially houbara bustards. One BirdLife International estimate puts the annual toll taken by falconers to be at least eight percent of the Asian houbara population. Meanwhile, local subsistence hunters throughout the birds' range zero in on the birds, while cattle chew up their habitat. Even where protection laws are on the books, such as in Kazakhstan, houbaras still fall to hunters and falconers.
More Danger in the Grass
Far off in Australia, the retreat of the Australian bustard echoes that of the houbara, but with different twists. "Bustards have all but disappeared from southeastern Australia and are less abundant elsewhere," says ornithologist Fitzherbert, who works at the Hobart-based Australian Bush Heritage Fund. "The main reasons for this are loss of habitat in southeastern Australia—caused by a combination of intensive agriculture, invasion of native grasslands by woody weeds, and also by hunting and fox predation." Native acacias rank high among the encroaching weeds, spreading because grassland-sustaining fires-once commonly set by hunting Aborigines-are now suppressed. Introduced red foxes (Vulpes vulpes) prey on the birds, while other introduced animals-rabbits, sheep, and cattle-damage their fragile habitat. Due to widespread declines, the species is considered near threatened.
The road is even rockier for other species. Cattle herds trample the endangered great Indian bustard's (Ardeotis nigriceps) eggs, inching this species, estimated at fewer than 1,000 birds, closer to extinction following centuries of habitat loss and over-hunting. The Bengal florican's (Houbaropsis bengalensis) prospects seem the bleakest of all: As few as 250 birds or as many as 1,000 may survive in isolated, highly endangered habitats along the India-Nepal border and in Cambodia and Vietnam.
The great bustard, despite a once-huge breeding range, is now one of Europe's most endangered birds, primarily due to habitat loss. Birdlife International's Collar dreads what may have happened to the now-troubled Portuguese populations he once studied. "I'm rather frightened to go back to my old study sites," he says. Today, Portugal's declining population supports between 500 and 1,000 birds.
The species has a tiny toehold in Morocco, but this too is slipping away. "I'd say this is one of the most endangered bustard populations in the world," says Alonso, who is involved in efforts to save Morocco's bustards. "The species is protected by law but in Morocco there is little space left for them. They stay in the few places where there is nobody. It's difficult to tell, but we guess there are fewer than 200," he says.
"Spain's is the last great bustard population that may end up surviving in the long- or mid-term," says Alonso. There, about half of the world population-about 20,000 birds-remains more or less stable [see "España Verde: Spain's Living Landscape," in the September/October 2001 ZooGoer]. "I think the European concern is concentrated on keeping this population alive because other populations have decreased. Take, for example, the case of Hungary, where in only 20 years, the population has declined from about 10,000 to just over 1,000 where it is today." Yet even in Spain, conversion of traditional and varied farmlands into large-scale, mechanized, often irrigated modern farms wipes out the bustards' and other grassland birds' habitats. Most of the birds live in four or five scattered strongholds.
Enough Room for Bustards?
Setting aside reserves may not save some far-ranging bustards. Entire landscapes must sometimes be conserved because any break in the birds' wide-open, treeless habitats may block the birds from moving, hampering genetic interplay between populations. The great's smaller cousin, the little bustard, declined in step with the loss of its once-widespread steppe habitat, disappearing from 11 European countries. A 1994 study published in the journal Biological Conservation concluded that to survive, little bustards need expansive, varied mosaics of open areas with vegetation high enough to hide the birds while short enough to allow them to scan for predators.
Biologist Carmen Martinez, author of the study, wrote: "I suggest that land managers should be given an incentive to increase the agricultural mosaic in cultivated areas. This could be achieved by the temporary set-aside of cultivated land and by increased cultivation of legumes (an important food)." Similar recommendations have been made for great bustards, but with few encouraging results to date. Despite a decade of talking about such programs in Europe, farmers and conservationists have yet to see eye to eye on how to balance traditional farming practices with a good bottom line.
In the case of little and great bustards, the European Union has mandated establishment of Important Bird Areas (IBAs) in Europe, where farmers should manage the landscape to benefit both themselves and grassland birds. However, local jurisdictions often overstep the goals of these areas, compromising the birds' welfare with special exceptions—additions like houses, power lines, and roads. Despite this, the plan is the best international effort yet to assess bustard status and set a course of action. Currently, 74 designated IBAs support great bustard breeding populations in ten countries. IBAs for Africa have just been drawn up, and protective legislation exists in many countries where declining bustards live. One of the biggest challenges now is sticking to the rules.
Bustards face other dangers as well. For instance, power lines strung between fields kill more individual great bustards in Spain than any other mortality cause since hunting was banned there in 1980. Power line collisions remain a problem throughout bustard habitats, and proper planning and placement of these structures, along with roads, will be critical in preserving bustards' grassy haunts. In addition, widespread pesticide use wipes out the birds' insect prey, an especially acute danger while young, just-hatched bustards are growing. Other pesticides sprayed in bustard habitat may kill the birds outright.
Returning bustards to former haunts requires hard work, a lot of money, and available habitat, and there are no guarantees of success. For example, in the 1970s, efforts to reintroduce great bustards to Great Britain-where they went extinct more than a century ago-failed. "They came to the conclusion very, very early on that it was impossible to reintroduce the great bustard," says Collar. "They need very large numbers of insects for their young to develop. We don't have that volume of grasslands any more in Britain. We don't even have grasslands. It was an idle dream." Projects in Austria, Hungary, Slovokia, and the Ukraine met a similar fate or are struggling. Despite the odds, British scientists are again studying the possibility of reintroducing bustards at a grassy military installation near Wiltshire.
Since 1986, a Saudi Arabian zoo breeding and reintroduction program has yielded better results with houbara bustards. This project, run by the Taif, Saudi Arabia-based National Wildlife Research Center, produced more than 1,500 chicks, and hundreds have been released into the wild. In 1995, the first confirmed wild nesting of reintroduced houbaras was documented, nine years after the project began. However, as the houbara habitat study found, reintroduction efforts will succeed only if expansive over-grazed areas grow back while grazing and hunting are kept to a minimum.
What does the future hold for bustards? A lot depends upon the species, its available habitat, and the home countries' ability and willingness to protect them. Often incompatible with people, bustards are "high-maintenance" species frequently requiring human restraint or intervention to prevent their disappearance. Many countries probably cannot make the sacrifices necessary to protect them. Even in affluent countries, keeping bustard habitats intact proves a tough challenge. Recently I read in the news about Spain's $22 billion plan to divert water from its soggy north to its parched south in order to irrigate dry farmlands, and I wondered: Will there be enough room for bustards?
Even the kori, that familiar safari sight, has no guarantees. In many parts of its breeding range, populations have dropped and isolated populations have vanished, mostly due to habitat change, including overgrazing. "As long as there are big parks and water-limited areas in southern Africa, the kori will be okay there," says Osborne. "But if aid money is available to dot the landscape with water holes, then cattle farmers will follow and the birds will slowly disappear."
MORE! At the Zoo: Bonus Bustards!
-Howard Youth, a Contributing Editor to ZooGoer, admires courting bustards' bold, brash ways.
ZooGoer 31(2) 2002. Copyright 2002 Friends of the National Zoo. All rights reserved.
