Related Resources
Watch videos of lekking birds:
Greater Prairie-chicken from The Nature Conservancy
Lesser Prairie-chicken from the Internet Bird Collection
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Lekkin' Grouse on the Prairie
Listen nowThe words leks and sex are related, and by some cosmic coincidence they even rhyme. Lek is a Swedish term for "sex play" or "mating sport." It also is a scientific term for a spot where males of a certain species convene to strut their stuff en masse, competing head-to-head for the favors of onlooking females.
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| A lesser prairie-chicken male displays at a lek in New Mexico. (Gary Kramer/NRCS) |
Lekking species include the walrus (Odobenus rosmarus), some fruit bats, zippy little rainforest birds called manikins (Pipra spp.), and a few antelope species. But the most famed lekkers are grouse. In fact, the term lek was first coined in the 1867 book The Game Birds and Wild Fowl of Sweden by author Llewelyn Lloyd, to describe Scandinavian grouse courtship behavior.
Of the world's 19 grouse and ptarmigan species in the subfamily Tetraoninae, only seven defend small territories on large leks. Five of these—the greater and lesser prairie-chickens, sharp-tailed grouse, and greater and Gunnison sage-grouse—live in North America. Over the centuries, males in these species have captured not only female grouses' attention, but also the notice of ornithologists and the imagination of the birds' human neighbors.
Native Americans, for example, emulated the spring mating rituals of prairie-chickens on North American plains with their wriggling, shaking, stomping, and feather-flipping prairie-chicken dance. Prairie-chicken dances held an honored place in many powwows, and—like the birds' displays—took place after harsh prairie winters. Mimicking the prairie-chickens, male dancers pranced around inside a circle, their female counterparts watching from outside the ring. The strutting display of sage-grouse and the tail-pointing of sharp-tailed grouse also inspired Native American dancers.
The bizarre choreography, ritualized dances, and otherwordly sounds of lekking-grouse displays take full advantage of the wide-open spaces inhabited by these birds. At traditional lekking grounds, the birds assemble before sunrise and activity peaks not long after the sun peeks over the flat or hilly horizon. Although predators often come calling early in the morning, they may not stop the show for long. "I've seen a golden eagle flush a greater sage-grouse at a lek," says wildlife photographer Robert E. Mumford, Jr., who has photographed all of North America's lekking grouse. "But soon after, the grouse walked or ran back in to the lek." In 1908, ornithologist Frank M. Chapman noted how quickly displaying greater prairie-chickens converted from gaudy exhibitionists to dingy, round-bodied birds. He wrote: "The sight of a passing hawk changes the grotesque beplumed, be-oranged bird into an almost invisible squatting brownish lump, so quickly can the feathers be dropped and air sack deflated. With woodland birds so great a change is unnecessary, but the prairie hen can hide only under its own feathers." Recent research indicates that some males set up leks in areas with less long-range visibility, which may reduce their vulnerability to predators.
Compared with non-lekking grouse and many other birds, these males defend small individual territories within their lekking grounds. Sage-grouse, for example, defend territories of between six and 120 square yards, on leks that may span two-and-a-half to 40 acres. Greater prairie-chicken males average territories of 620 square yards, an area roughly one-ninth the size of a football field. Lesser prairie-chicken and sharp-tailed grouse turf is even smaller—between 50 and 180, and 55 and 310 square yards, respectively. Non-lekking grouse typically defend larger areas. Males of the forest-dwelling ruffed grouse (Bonasa umbellus) of northern North America, for example, defend territories of more than five acres, an area that could accommodate five football fields or more.
On a sage-grouse lek, up to 70 males may be present, standing as close as a few feet, or as far as 300 feet, from their nearest competitors. For prairie-chickens and sharp-tailed grouse, numbers are usually lower, with each lek hosting somewhere between eight and 40 displaying males. Males cluster along their territories' edges, facing off and often scuffling. During skirmishes, male sage-grouse buffet each other with their wings, but rarely peck or scratch at each other in midair like prairie-chickens and sharp-tailed grouse.
Male lekking grouse perform stereotyped and, to human eyes, outrageous breeding displays. Females appear to select the few top lekkers with the showiest plumage and most vigorous struts. Once females make their choices, mating lasts but a few seconds. A male may mate more than 20 times in a morning, changing mates every two minutes. One sage-grouse male in Montana was observed mating 169 times in one breeding season.
All of the strutting, jumping, stomping, hooting, popping, and fanning ends in results males do not quickly see. After the dominant males are chosen by females and mating occurs, the females leave the leks and prepare to nest. Males do not aid in nest-building, incubation, or feeding of the young.
No one knows for sure how much longer these rituals will continue. Once common across wide-open wilderness expanses, lekking grouse are all losing ground to human-caused landscape changes and other forces.
"Chickens" of the Prairie
There are three species of prairie grouse, and all belong to the genus Tympanuchus: the greater and lesser prairie chickens, and the sharp-tailed grouse.
Barred in dark brown, cinnamon, and buff, prairie-chickens resemble, in size and general shape, striped poultry. They certainly filled many a Native American and prairie settler's cooking pot. The greater prairie-chicken (T. cupido) inhabits tall-grass prairie, and one subspecies—the heath hen (T. cupido cupido)—was found in open grassy parts of the Northeast until 1932, when the last disappeared from Martha's Vineyard, Massachusetts. The lesser prairie-chicken (T. pallidicinctus) lives in semi-arid shortgrass prairie, now mainly in a distribution resembling a fading crescent that runs from the far western corners of Kansas and Oklahoma to extreme eastern Colorado and New Mexico, then south to the Texas Panhandle.
Ronald L. Westemeier, a retired biologist and prairie-chicken expert, has studied and worked to protect isolated greater prairie-chicken populations at the current eastern terminus of their range in Illinois. After more than 30 years of study, he still raves about the birds' activities. "It's quite a spectacle. They do their breeding displays on a communal grounds that requires wide open spaces. Bare ground is the best," he says. The lekking spectacle, called "booming" in prairie-chickens, picks up momentum in March, when the normally drab, furtive birds first step out into the open. It peaks by mid-April, peters out by May.
"If the females come in, the males get all excited," says Westemeier. "But probably only ten percent of males are involved in actual copulations." When prairie-chicken competitions are in full swing, the males display in a frenzy. With lowered heads and raised tails, they inflate brightly colored, bubble-like sacs on the sides of their throats, and raise dark feathers on their heads that resemble rabbit ears or, as the greater prairie-chicken's species name, cupido, suggests, the wings of Cupid. They rapidly stomp their feet while emitting moaning or gobbling calls; rivals hop at each other and may also leap into the air, making cackling sounds. The moan, or hoot, of the greater prairie-chicken can carry more than two-and-a-half miles across the birds' open habitat.
The most adaptable, and least rare, prairie grouse is the sharp-tailed grouse (T. phasianellus), revered and sought by hunters from Wisconsin to eastern Alaska. Although their traditional habitats include steppes, grassland, and open shrubby areas, sharptails now often occur in farm fields, and will even lek there on slight rises where there is little vegetation.
The sharp-tailed grouse is not only loved for its explosive flight and lean, gamey breast meat: People adore its showy lek antics, too. In fact, the town of Ashern, Manitoba, where rodeos, hunting, and fishing are among the most popular recreational activities, hails itself as "The Land of the Sharptail Grouse." Its most remarkable landmark is a 20-plus-foot-tall statue of the region's most sought-after fowl.
Sharp-tailed grouse sport elongated central tail feathers. To exhibit these showpieces to full advantage, males duck their heads and spread and lower their wings, and point their tails skyward like white-and-tan arrowheads. They cackle, coo, whine, bark, gobble, and make popping sounds with the air sacs. They face off, rattle their tail feathers, and quickly stomp their feet during their fervent dance displays, increasing the pace when females show up to watch. The lek may turn violent when males tug at competitors' feathers or attack them with their beaks, wings, or nails.
Grouse of the Sage
The largest grouse in North America is the greater sage-grouse, followed close after by the Gunnison sage-grouse. These two species are on average about 24 inches long, as opposed to Tympanuchus grouse's 15-to-17-inch length, and are more visually stunning. They puff out immaculate white breast feathers punctuated by two large yellow air sacs in the middle of their chests. They strut around with wings held low and blackish tail feathers splayed and pointed up like spiked turkey tails.
"Sage-grouse are slow-steppers and they never hop into the air like prairie-chickens," says Jessica Young, associate professor of biology at Western State College of Colorado in Gunnison. "In addition, they don't have drumming feet and their air sacs are much lower on the front of their bodies, part of the esophageal pouch, or chest. They pop their air sacs instead of hooting like the prairie-chickens, and their tails are held upright throughout their strut display." The bubbly popping sounds are generated when the air sacs quickly deflate.
Young is an expert on the Gunnison sage-grouse (Centrocercus minimus), a species split by taxonomists from the more widespread greater sage-grouse (C. urophasianus) in 2000. Gunnison sage-grouse, which now live only in western Colorado and eastern Utah, reach only two-thirds the size of greaters, and their plumage and lekking activities differ in some ways. "They throw their neck feathers, or filoplumes, over their heads," says Young, "and typically end their strut by shaking their tails." There are differences in the sounds they make as well. The Gunnison display occurs at a slower speed, with more air-sac pops per strut than in greater sage-grouse.
Something to Grouse About
The time to take conservation action to save all the lekking grouse is now. All five North American lekking grouse have suffered serious declines over the past 150 years, with some of the most rapid changes occurring over the last few decades. Both the lesser prairie-chicken and Gunnison sage-grouse, for example, have been candidates for listing under the Endangered Species Act. In April 2006, however, the U.S. Fish & Wildlife Service (USFWS) refused to list the Gunnison sage-grouse and dropped it as a candidate, in part due to disagreement over the degree of decline the species has undergone in recent decades. Meanwhile, also in 2006, the National Audubon Society declared this bird one of the ten most endangered in North America. The Gunnison's habitat has been reduced to less than nine percent of its original extent, and the remaining populations total perhaps 4,000 to 6,000 birds in the spring, when researchers count them and before nesting begins.
As few as 20,000 lesser prairie-chickens remain, in former Dust Bowl areas. Numbers are down more than 90 percent since the 1960s, with a majority of birds in Kansas and New Mexico, and lower numbers in Texas, Oklahoma, and eastern Colorado. The species is the focus of a new joint effort between the USFWS and the Texas Parks & Wildlife Department to recruit private landowners to voluntarily protect the birds and their grassland habitat. For their efforts, participating landowners will not face any land-use restrictions or conditions if the bird is federally listed. In 1998, the USFWS decided that, due to substantial declines throughout its five-state range, the species designation under the Endangered Species Act would be justified, but the designation was not made after a finding that listing was "warranted but precluded." A 1998 USFWS press release read: "Protection of the lesser prairie-chicken under the Federal Endangered Species Act is justified but other species in greater need of protection must take priority in the listing process… ." It has been a listing candidate ever since.
The largest remaining greater prairie-chicken populations are found in parts of Kansas, Nebraska, and South Dakota, with smaller numbers in North Dakota, Minnesota, and other Plains states. Many small satellite populations, like those in Illinois, face uncertain prospects. Yet even in places with the largest populations, such as in the Flint Hills region of eastern Kansas and northern Oklahoma, recent trends in cattle ranching that include early spring burning and intensified stocking of pastures may be contributing to steady population declines. Conservationists recommend lessening grazing pressure and providing more of a mosaic of tall and short grasses to ensure a healthy coexistence between cattle and grassland wildlife in this region.
Prairie-chickens sometimes descend upon soybean, milo, and other agricultural fields in late fall and winter in large flocks, but while grain in these fields provides important food at times of shortage, farmlands constitute only a small percentage of prairie-chicken habitat, most of which must remain in grassland for populations to survive.
When first described in 1805 by the Lewis and Clark expedition, the greater sage-grouse was common and widespread across much of the West. Since then, and especially since the 1950s, populations throughout the bird's range have declined. Today, about half of the greater sage-grouse's sagebrush habitat has been lost to overgrazing, development, gas and oil exploration, and road-building. In areas that remain, the bird's presence says much about how well its habitat is faring. "I would call the sage-grouse a wonderful indicator species of sagebrush and shrub-steppe ecosystems," says Young. Sage leaves and buds constitute an important part of the bird's diet, especially in fall and winter, and it does best in heterogeneous sagebrush habitats that include dense, sparse, old, and young patches of vegetation.
Yet even where ideal habitat remains, changes may soon be underway. A 2005 Oregon State University and U.S. Forest Service study predicted that sagebrush ecosystems may be cut to a fraction of their current size by climatic changes wrought by global warming. In addition, since 2006, greater sage-grouse deaths from West Nile virus have been reported in eight states, indicating that the disease's spread may be a further threat to these birds.
The sharp-tailed grouse has also declined in many of the southern and eastern parts of its range due to habitat alteration. It occupied 21 states and eight Canadian provinces but is now gone, for example, from California, Illinois, Kansas, Nevada, and Oregon.
The abundance of lekking grouse once seemed as unshakable as the plains and sagebrush ranges that stretched across the horizon. Ranchers, farmers, hunters, and birders still enjoy watching the early-morning spring rites of the lekking grouse that typify the wide-open range. But the performances play at fewer venues each year. Today, these birds seem to be riding an imaginary pendulum, one that could swing toward the heath hen and extinction, or toward an endless continuation of the "sex play" upon which these species depend for survival.
—Contributing editor Howard Youth's last ZooGoer article focused on Asia's clouded leopards.
ZooGoer 3(2) 2007. Copyright 2007 Friends of the National Zoo. All rights reserved.
