Bringing the Boom Back to Missouri
It is still dark as I drive down the deserted streets of Browning on a chilly April morning. I am meeting George Shurvington, a conservation resource technician who is releasing eight prairie chickens, reintroducing them to their historic range of northern Missouri.
The greater prairie chicken has been considered a rare bird in Missouri for much of this century. When settlers first came here 200 years ago, millions of prairie chickens inhabited the northern and western parts of the state. Many Missourians remember seeing prairie chickens through the 1950s. In the 1960s, however, the population plummeted.
Cause of the decline is primarily loss of habitat. The prairie chicken population in Missouri now is estimated at only 2,000 birds. The eight birds Shurvington is releasing this morning are part of an ongoing Conservation Department effort to return prairie chickens to our state's grasslands.
As I open the passenger door of George's muddy grey Dodge Ram truck with the familiar Conservation Department triangular logo on its side, I hear wings rustling inside two large wooden boxes in the pickup bed. The birds, trapped in Nebraska, have had a long night of travel. We begin driving toward the designated release site, a private pasture on the Linn-Sullivan county line.
The decline of the prairie chicken population mirrors the loss of our state's native tallgrass prairie. Less than 1 percent of the original 12 million acres of native prairie remains. Extensive cultivation of native grasslands severely reduced the prairie chicken's nesting and brood-rearing habitat. The control of prairie fires that naturally maintained grassland habitat contributed to the bird's decline. So did overgrazing and excessive hunting. Prairie chickens once were prized game birds in Missouri, explains George, but their decreasing population brought the hunting season to a close in 1906.
In an experimental program, the Conservation Department released prairie chickens in north-central Missouri in the springs of 1993, 1994 and 1996. In 1996 the total release was 98 birds, half of them male and half female. The birds came from Kansas and Nebraska.
The Conservation Department released the birds onto Missouri lands historically used by prairie chickens and determined by biologists to support good habitat. Most of these sites are privately owned. Landowners and farmers in north-central Missouri take pride in the unique opportunity to play a part in a successful conservation effort.
Larry Mechlin, the research biologist heading up this experimental release program, says, "Only through the establishment of a population that maintains itself through the years can we claim success. However, we're pleased with the results so far. Some birds have remained in the general area of release, while others are quite mobile and have moved as far as 25 miles.
"Since both types of birds have attempted to raise young, we consider this a positive attribute. Without doubt they're better at selecting proper prairie chicken habitat than a biologist. The other measure of success is the establishment of booming grounds, and we know of four."
George shifts the pickup into low as we pull off the gravel road and make our way to the designated release site. We stop on top of a hill where we see rolling grassland in all directions. The sun is just rising over a pond in the distance, and a few ducks noisily land on the water.
It is easy to distinguish the sound of a nearby prairie chicken booming ground. Each spring, male prairie chickens display a colorful courtship ritual on their booming ground. Their distinctive call sounds like the noise children make when pursing their lips and blowing across the top of a soda bottle. The wind catches the males' eerie song and carries it across miles to both listening humans and prairie chicken hens.
Most of the trees I see at this release site hug the edge of the pond, away from the panoramic expanse of grassland. It is important not to release the birds onto islands of grass surrounded by trees. Hawks are effective prairie chicken predators. The proximity of trees would give the hawks a ringside seat for an easy meal.
The grass where George has set the wooden release boxes begins to take on a pink tint as the sun inches higher. Both the prairie chicken release boxes and traps have been specially designed by Conservation Department staff. The traps are small rectangular cages, approximately 3 feet wide, 5 feet long and 2 feet high.
Conservation Department biologists place these traps on a booming ground with 2-foot-high wire drift fences that funnel the birds into the trap opening. When on their booming ground, the prairie chickens are territorial and focused on the mating activity at hand; the presence of the cages does not scare them away.
The birds do not seem to understand wire, and they walk into the traps without any kind of bait. Biologists control the trap doors; if they just need females, for example, they will allow males to wander freely in and out of the trap.
Once caught, a bird is put into a pillowcase so it cannot hurt itself. Half of the males and half of the females caught are equipped with radio transmitters around their necks. All males are fitted with a unique combination of color bands so each bird can be individually identified if later seen on a booming ground. The transmitters allow biologists to monitor survival and nesting efforts of birds and to locate newly established booming grounds.
When booming grounds are located, birds can be counted each spring to follow the growth of the population and the survival of leg-banded males. Mechlin says, "Survival is relatively low for males in the spring because they are most vulnerable when spending so much time displaying on the booming grounds. Females are most vulnerable while nesting, but all birds seem to survive at a higher rate when fall arrives."
Once trapped, the birds are then put into wooden release boxes. The release boxes have four separate compartments, each compartment holding one bird. The prairie chickens were transported in these boxes and released within 24 hours of capture.
George has attached a wooden pulley to the top of each release box and has threaded a string through the mechanism. He walks backwards with the strings about 30 feet and prepares to pull open the doors.
"The birds I've released have headed directly toward that booming ground we hear," he explains. As if out to prove him wrong, the birds fly in the exact opposite direction from the booming noises when he yanks the string and the doors pop up.
We decide to visit a neighboring booming ground to watch the annual spring-time show. Prairie chicken booming grounds generally are located on elevated grassland sites with short vegetation. In a fascinating display of instinct, some of the reintroduced birds in north-central Missouri have established their booming grounds in exactly the same locations as birds studied in the mid-1940s.
The prairie chicken breeding season begins in early spring and extends through June. Males make morning visits to the booming grounds, flying in before the sun begins to rise. They puff and prance, establishing dominance and trying to attract a female's attention. The hens fly in as if they are going to market and coolly survey the selection of males.
The noise level dramatically increases when a hen arrives. The booming noise rises, punctuated with whoops and cackles. Males puff out bright yellow-orange air sacs on the sides of their heads and spread out their tail feathers to do a quick shuffle dance across the ground. Two males pair off and flap into the air as if they are shadow boxing. A nearby hen seems not to notice them.
The Conservation Department has been studying prairie chickens since the early 1940s, when a young biologist, Charles Schwartz, began mapping the remains of the declining Missouri prairie. The comprehensive management plan the Conservation Department now has in place for prairie chickens should increase the number of birds by stemming the loss of grassland habitat and reintroducing birds to vacated habitat. The long-term goal is to have more prairie chickens and more diverse grassland landscapes to benefit all grassland wildlife.
Farmers are increasing bird habitat with careful management techniques, such as planting cropland with specially formulated grass seed mixtures, regulating grazing, occasionally burning grassland, leaving patches of crops unharvested and postponing mowing until after the nesting season.
Many Missourians once took the sights and sounds of this spectacular bird for granted. Often we do not appreciate our natural wonders until it is too late, but Missouri has been given a second chance at stewardship with the prairie chicken.
If the program succeeds, future generations of Missourians will not have to be told stories of prairie chickens. They will be able to wonder at the ancient booming grounds themselves.