Prairie chickens are birds in trouble. The greater prairie chicken (Tympanuchus cupido), is basically a bird of the tallgrass prairie region, that fact alone explaining in part why prairie chicken numbers have declined. Less than four percent of the original tallgrass prairie remains unturned by the plow, most of that concentrated in a few large tracts in the Flint Hills of Kansas and part of Oklahoma.
If most people know about prairie chickens at all, it is that they gather at leks in the spring where the males put on acrobatic displays and strut about for the benefit of the hens. Greater prairie chicken males make a sound something like blowing over an empty pop bottle while they are trying to impress the females. Known as booming, it is a sound, along with the dance and the vigor of this virile ritual that draws birdwatchers to the Kansas prairies each spring.
Now those concerned about prairie chickens wonder whether a competing and more commercially marketable sound – that of the wind – will impact the chickens’ booming. Research being conducted in this area under the direction of KSU biology professors Samantha Wisely and Brett Sandercock seeks to determine how the development of wind energy might impact prairie chickens.
The research is funded by Horizon Wind Energy, PPM Energy, FPL Energy,
Kansas Department of Wildlife and Parks, the Kansas and Oklahoma offices of the Nature Conservancy as well as federal agencies such as U.S. Fish and Wildlife Service and the Department of Energy’s National Renewable Energy Lab. Recently, BP Wind Energy and the National Fish and Wildlife Federation.
Moreover, Horizon Wind Energy, Greenlight Energy and DISGEN have granted the scientists access to proposed wind farm sites.
In Clay County, five researchers use dropnet and drift-fence-funnel type-traps to capture the birds and then band them for study. These birds will be followed to determine such factors as age, size, and to make estimates of apparent survival rates.
“Apparent survival is a statistical estimate of true survival that takes into account re-capture and re-sighting probabilities,” explained researcher Andy Gregory, a doctoral student in biology.
While all the birds are banded, only females are collared with a VHF transmitter because they are the only birds considered in the demographic study that includes gathering information on population size, growth, density and distribution of the birds.
“Hens are the real driving force in the prairie chicken population. If the hen can’t find good nesting habitat, then the chance of nest success is reduced,” said Robert J. Robel, an emeritus professor biology at KSU and an expert on prairie chickens.
The researchers set up blinds as part of their method to observe chickens at leks. There they make bird counts and observe their behavior.
“The greater prairie chicken is a charismatic species that acts as an indicator species for tallgrass prairie habitat,” said Gregory. “The Flint Hills is one of the last remaining tracts of tallgrass prairie left in Kansas. Prairie chickens ought to be doing well there.”
Robel said the reasons for the sharp decline in prairie chicken populations are many and varied.
“Spraying and burning of grasslands has affected insect populations. Not only by reducing the insect population but also by changing the species of insects available to prairie chicken chicks. Different species of insects may influence the health and wellbeing of the chicks as different insects vary in nutritional value.
“Insects prefer rangeland with lots of forbs interspersed. Pastures that are grazed heavily often have a reduction in succulents that support good populations of insects. But sometimes overgrazing leads to an increase in forbs and woody plants and results in less grass.
“While prescribed burning may improve the nutritional value of grass for cattle, it can reduce nesting cover for prairie chickens. They use last year’s standing dead grass for nesting. And a lack of cover during the nesting season makes the nests more vulnerable to predation,” said Robel.
From the prairie chicken’s standpoint, it would be better if ranchers burned only parts of a pasture each year instead of the entire pasture at once. That way there would be some old growth for nesting and cover.
“In addition, there are simply more predators now than there were 40 or 50 years ago. Some studies have indicated a ten-fold increase in mammalian predators,” Robel said.
Predators of adult greater prairie chickens and their chicks include: various hawks, owls, eagles, skunks, coyotes, opossums, badgers, weasels, mink, foxes, raccoons, as well as dogs and cats. Toss in snakes, crows and a few other enemies with most of the above predators and greater prairie chicken eggs are also at risk.
Prairie chickens are valued as an upland game bird and in Kansas and several other states including Nebraska and South Dakota, their numbers are still strong enough to support a hunting season.
In addition to predatory dangers, ring-necked pheasant hens sometimes victimize prairie chickens by laying eggs in prairie chicken nests. Because the pheasant eggs hatch a few days faster than the prairie chicken’s own eggs, the prairie chicken hen leaves the nest early and her eggs fail to hatch.
By Elby Adamson
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