Breading season demographics of a lesser prairie-chicken (Tympanuchus pallidicinctus) population in the northeastern Texas panhandle

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2012-12

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Abstract

Lesser prairie-chicken (Tympanuchus pallidicinctus) populations have declined across their range since 1900 and are a candidate for listing as Threatened under the Endangered Species Act. The historic lesser prairie-chicken range included all of the Texas panhandle. Currently, lesser prairie-chickens are found in 2 distinct populations in the northeastern and southwestern Texas panhandle. I conducted a 3-year study of breeding season demographics of lesser prairie-chickens on private properties in Gray and Hemphill counties (1 March-31 August, 2008-2010).
I estimated male and female breeding bird survival, nest survival, and chick survival. I used demographic data collected during this study to conduct a population viability analysis and estimate time until extinction in the northeastern Texas panhandle. I assessed the efficacy of traditional road-based lek surveys to monitor lesser prairie-chicken populations in the Rolling Plains and High Plains ecoregions of Texas. Male survival differed between seasons and age-classes. Juvenile male survival was 1.00 (SE=0.00) during the lekking season and 0.88 (SE=0.62) during the nesting season. Adult male survival was 0.51 (SE=0.10) during the lekking season and 0.82 (SE=0.08) during the nesting season. Female survival did not differ with respect to season or age and was 0.55 (SE=0.13) for the entire breeding season. Nest survival was 0.36 (SE=0.05) during my study. Chick survival was lower between hatch and 14 days post hatch (0.18; SE=0.01) than 15-63 days post-hatch (0.55; SE=0.16). Results of a population viability analysis indicated low population growth rate (=0.44) and time to extinction was 3.5 years under baseline conditions based on field data. Management practices resulting in higher vital rates across the annual cycle resulted in higher population growth rates and longer times until extinction. The probability of detecting an active lek during road-based lek surveys was affected by wind speed, wind direction, and ecoregion. Current assumptions of detectability of active leks are likely too great and should be adjusted based on environmental conditions. Due to the drastic reduction in lesser prairie-chicken population across their range, listing as threatened is likely. As such, it is important to collect demographic data and establish management plans for species recovery. The results of analyses based on the data collected during my study suggest that the lesser prairie-chicken population in the northeastern Texas panhandle are on the brink of extripation.

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Keywords

Lesser prairie-chicken, Northeastern Texas panhandle, Population viability analysis (PVA), Lek survey

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