Expected Impacts on Greater Prairie-Chickens of Establishing a Wind Turbine Facility Near Rosalia, Kansas, Part Two

Greater prairie-chicken population trends in North America
Few estimates exist for greater prairie-chicken population numbers in North America prior to the 1960s. However, the numbers of these birds were sufficient to support subsistence and market hunting in several of the Great Plains states in the late 1800s and early 1900s (Hier 1999). Most state wildlife agencies began to monitor greater prairie-chicken populations by the mid 1960s. Generally this monitoring consists of counting males displaying on breeding grounds (leks) in the spring, adjusting the survey numbers to account for the female portion of the population, and extrapolating those numbers across the known habitat of the greater prairie-chicken. The validity of such a practice is questionable (Applegate 2000) and the accuracy of the estimates is dubious at best. Even so, those data, if collected in a consistent manner each year, probably reflect trends in greater prairie-chicken populations over time. Svedarsky et al. (2000) summarized the recent population estimates of state wildlife agencies across the range of the greater prairie-chicken and reported the following for states which permitted hunting those birds and for states in which hunting did not occur.

	Estimated numbers of greater prairie-chickens
Year	Hunting permitted (4 states)	Hunting not permitted (7 states)
1968	760,000	18,860
1979	1,200,000	17,672
1985	740,000*	16,054
1989	742,000*	14,268*
1997	371,484	14,758
	* incomplete data set

The above estimates disclose a 60 to 70% decline in the greater prairie-chicken population of North America between 1968-79 and the late 1990s. This population decline has raised concerns over the future viability of greater prairie-chicken populations in the Great Plains states.

Greater prairie-chicken population trends in Kansas
The most recent review of the status of the greater prairie-chicken in Kansas was conducted in the late 1990s (Applegate and Horak 1999). That review documented the early legislative actions that established prairie-chicken hunting seasons in Kansas. Those hunting regulations probably reflected prairie-chicken populations, i.e., being liberal when birds were abundant and restrictive when populations were low. Generally in the 1860s, the hunting seasons were long, statewide, and had few restrictions. Farming activities of the early settlers in the 1870s benefited prairie-chicken populations to the point that the hunting seasons were very liberal, essentially prairie chickens could be killed by anyone, anyplace, by any means, any time of the year. The combination of an increased food source provided by small-grain agriculture and expansive tallgrass prairie habitat resulted in an abundance of greater prairie-chickens in the late 1800s. As agricultural activity expanded at the expense of the tallgrass prairie habitat, prairie-chicken populations declined.

The decrease in prairie chicken numbers was reflected by the closing of prairie-chicken hunting seasons and reductions of daily bag limits in the early 1900s (Wood 1964). In 1905, Butler County closed the prairie-chicken hunting season for 3 years. The prairie-chicken hunting season was closed in all of Kansas from 1913 to 1916. Between the 1920s and 1957, there was a mix of closed and open prairie-chicken hunting seasons, variable bag limits, season lengths, and legal shooting hours. These changes coincided with the establishment of the Kansas Forestry, Fish and Game Commission in 1921 (now Department of Wildlife and Parks); severe drought conditions of the 1930s and 1950s; changes in agricultural activity and overgrazing by livestock; and natural fluctuations of prairie-chicken numbers (Applegate and Horak 1999). Since 1957, Kansas has permitted the hunting of greater prairie-chickens each year. From 1957 to the early 1970s, the hunting seasons were 2 to 11 days in length; whereas, in the 1970s and early 1980s they generally ranged from 30 to 90 days. In 1989, an “early season” was established which added 31 days to the 86- to 91-day hunting season from 1989 through 2001. The daily bag limit for greater prairie-chickens has remained at 2 since 1957.

Kansas began monitoring greater prairie-chicken populations in 1963. The annual surveys consist of lek counts of greater prairie-chickens during March and April. From these data, indices to greater prairie-chicken populations are generated for four physiographic regions in Kansas, and pooled for a statewide index. A Rural Mail Carrier Survey of greater prairie-chickens is also conducted four times per year, but is considered less reliable than the survey of displaying males on booming grounds or leks.

The lek-survey index is based on the number of birds counted on leks along 10-mile long routes (commonly a county road) in typical greater prairie-chicken habitat. It is assumed that all leks within one mile on both sides of the road can be detected during the survey, and the number of birds on those leks represents all of the males in the 20-square-mile survey area. The county data are converted to birds per square mile and used as the index to the greater prairie-chicken population for each route. The lek surveys of greater prairie-chickens began with 11 routes in 1963 but now consists of 28 routes. Generally no more than one survey route is located in any single county.

Over the years, the stronghold of the North American greater prairie-chicken population has been the tallgrass prairies of Kansas, primarily the Flint Hills region of eastern Kansas (Applegate and Horak 1999, Svedarsky et al. 2000). The lek surveys conducted in Kansas since the early 1960s reflect a statewide decline in the greater prairie-chicken population. The average multi-year statewide greater prairie-chicken population index fluctuated between 7.6 and 8.2 birds per square mile between 1963 and 1989, but decreased to 5.5 for the 1990-99 period, and was 4.8 for 2000-02. The index to greater prairie-chicken populations in the Flint Hills region of Kansas has fluctuated over the years, but has not reflected as great a decline as the statewide index. Below is a summary of the 1963-2002 statewide and Flint Hills region indices to greater prairie-chicken populations obtained from various Kansas Department of Wildlife and Parks reports. The figures represent annual averages, but each is not necessarily based on data from the same number of routes each year.

Even though the above indices are widely accepted as reflecting long-term trends in greater prairie-chicken populations (Applegate 2000), no controlled research has been conducted to determine if they accurately reflect the number of birds present along the survey routes, and more importantly, in the region or the state as a whole. The lek surveys from which the trend indices are developed are conducted in March and April, therefore represent indices to the Spring greater prairie-chicken population.

Continue to Part Three