Cooperative Fish and Wildlife Research Units Program: Texas
Education, Research and Technical Assistance for Managing Our Natural Resources

The lesser prairie-chicken has experienced as much as a 97% decline in population size and similar declines in occupied area from historic levels. Causes of the population declines have been attributed to a variety of land-use practices, but the influence of surface water loss via drying of springs has not been evaluated. An unvalidated assumption that prairie-chickens do not require free water has been perpetuated for decades. The fact that recruitment is lower after drought years has been attributed to poor vegetation growth and low food resources; however, the physiological requirements for egg production and lack of water have not been a consideration. Based on data from other gallinaceous birds we estimate a hen lesser prairie-chicken needs at least 135 cc (0.6 cups) of water to set a clutch of 12 eggs. This suggests that in the absence of free water, hens are assimilating a volume of water amounting to approximately 20% of their own biomass for egg production. Limited availability of water would be expected to result in smaller clutch sizes with lower moisture content and, hence, viability, of eggs. We have found high visitation rates by hen prairie-chickens to surface water sources, 87% of which are during mating, nesting and brood rearing months. This suggests that water use is more closely tied to egg production than ambient temperature; hens did not visit water sources during the hottest months of July – September. We suspect free water is an important resource for successful reproduction by hen lesser prairie-chickens due to the physiological demands for egg production. Natural springs were once common in our study area, but have gone dry due to groundwater pumping. No study has examined the potential population level influences of artificial water sources on lesser prairie-chickens. We propose to take an adaptive management approach in experimentally assessing the influence of surface water availability on reproductive parameters of lesser prairie-chickens. If our hypothesis is correct, reproductive rates and success and, therefore, conservation of lesser prairie-chickens could be enhanced by adapting management plans to include providing access to surface water in the current prairie-chicken distribution. This may be especially important as a conservation and management tool during not only drought, but also as the region undergoes climate induced increases in temperature and aridity, with fewer precipitation events.