New hope arrives for endangered prairie chickens
Thu, 05/03/2012 - 3:15pm — jerekj
WAH-KON-TAH PRAIRIE, Mo. -- Greater prairie chickens, missing for some years among the grasses at Wah-Kon-Tah Prairie, strutted and boomed again this spring in an eons-old mating ritual. Biologists, digging deep in grassland ecology to save the species in Missouri, brought them back. Now, they watch to see if this iconic but state-endangered member of the grouse family can be restored longterm to prairies where they once thrived.
“Hopeful is the right word,” said Max Alleger, grassland bird coordinator for the Missouri Department of Conservation (MDC). “Perhaps our biggest question is whether intensive management can in the long run balance the fact that our grasslands are limited in size. Do we have enough grasslands to support prairie chickens on the landscape?”
A five-year translocation project by MDC to help answer the question concluded in April. MDC crews trapped Kansas prairie chickens where they are plentiful in the grassy Smoky Hills. Biologists then gave the birds leg bands and tiny radio transmitters before releasing them at Wah-Kon-Tah’s native grasslands north of El Dorado Springs.
Those prairie chickens will help land managers serve the species. Observers track the birds’ movements visually or via radio telemetry. Results tell researchers how habitat management can help the ground-dwelling birds sustain populations.
“In the last five years, I’ve learned a lot about prairie chickens from this study,” said Len Gilmore, an MDC wildlife management biologist based in El Dorado. “They like hanging out in the short grasses and feeding there, and they go to our prairies with taller grasses to roost at night.”
Prairie chickens this spring used three leks – courtship and mating sites – at the 3,000-acre Wah-Kon-Tah Prairie in St. Clair and Cedar counties. Some courting males and females were hatched and reared on the area, an encouraging sign that reproduction is occurring.
“The number of leks indicates the population is increasing,” Gilmore said. “They’re breaking off and forming new booming grounds.”
Prairie chickens once numbered in the hundreds of thousands in Missouri on wide-open grasslands and areas mixed with native trees, wildflowers and grasses. But cities, farming and fire suppression during the past two centuries altered landscapes the birds evolved upon.
Today, less than one half of one percent of Missouri’s original prairie remains, and those remnants are scattered. Prairie chicken flocks endured into the late 1900s on or near native grassland remnants in northern and western Missouri. But in recent years their numbers plunged to critically low levels – dozens rather than hundreds or thousands – and some flocks vanished.
Low reproduction due to poor weather conditions for nesting, habitat decline and predators are suspected contributors to decline, biologists theorize. Prairie chickens have a high natural mortality rate, 50 percent or more annually with birds generally living only a few years. Low numbers in flocks means high risk for the species.
The flocks living in the Wah-Kon-Tah area vanished by 2004. A small flock using MDC’s Taberville Prairie Conservation Area about 10 miles away survived in low numbers.
MDC began releasing Kansas prairie chickens at Wah-Kon-Tah in 2008 to see if prairie chickens could be re-introduced to a landscape where they once thrived. This spring, 19 males and 44 females were released on the native and restored grassland, which is a partnership between MDC and The Nature Conservancy of Missouri.
The tracking study is providing answers about their habits and surprises.
A landscape with diverse heights of grasses and forbs is important, Gilmore said. Prairie chickens like to build nests on the ground in taller cover. But they don’t like to nest too far from shorter grasses where they and chicks can easily move about, feed and rest. But 50 percent or more of an area should have grasses tall enough to provide good nesting cover. A lack of large quantities of high-quality nesting cover may have led to prairie chicken declines.
The study confirms that prairie chickens have a strong affinity for “high-clipped” grasses, places where plants are tall enough for them to duck and hide in, but also short enough for them to raise their heads above and watch for predators. Public land managers now use prescribed fire, cattle grazing, mowing and haying to get the variety in grass heights that prairie chickens prefer. Prairies or pastures left to grow rank without disturbance don’t serve prairie chickens well.
A surprise from the radio telemetry tracking is how far prairie chickens move about on a landscape. They easily move 20 to 30 miles across rivers, roads and wooded fence rows. They won’t feed and roost on the ground near tree lines but they will cross them on long journeys. One bird flew to Kansas and then returned. Another spent the winter in a crop field in northwestern Vernon County and then returned to Wah-Kan-Tah for spring.
There is surprising interaction between the flock at Wah-Kan-Tah and the one at the Taberville prairie. Prairie chickens have also moved to other prairie remnants or traditional lek sites that have not had birds in recent years, Gilmore said. The movement may be a species evolutionary survival skill for mixing genetics. Their ability to navigate back and forth across the countryside and their choices to settle in at places that held prairie chickens years ago is uncanny.
One concern was that with low numbers of prairie chickens, less genetic diversity could cause fewer eggs to be laid by hens. But thus far, clutch sizes are healthy with 11 to 14 eggs in nests.
As the translocation of Kansas birds ends, monitoring results are prompting MDC biologists to provide more variation and diversity in plant species and heights than what occurred in past decades on public grasslands. Partnerships with private landowners are also an important component in prairie chicken recovery.
“It’s very important that all the habitat pieces are lined up right,” Alleger said. “Prairie chickens are a worthwhile species. We’re trying to do our level best to keep them in Missouri.”