SPRING PRECIPITATION AND FLUCTUATIONS IN ATTWATERS PRAIRIE-CHICKEN NUMBERS - HYPOTHESES REVISITED

Two related hypotheses argue that greater than normal precipitation du ring May alone or spring (Mar-Jun) leads to decreased Attwater's prair ie-chicken (Tympanuchus cupido attwateri) breeding success, whereas le ss than normal precipitation during these periods leads to increased b reeding success. These hypotheses have been accepted by wildlife manag ers and, seemingly because of observer expectancy bias, have been used to explain annual variation in Attwater's prairie-chicken numbers. We demonstrate that neither hypothesis is supported by available data. S imilarly, alternative hypotheses that May or spring flooding, the date in May when maximum precipitation occurs, or precipitation variabilit y among spring months drives spring breeding numbers also were not sup ported. We found, however, that breeding success in spring can drive p roportional changes in breeding numbers the following spring.