Merriam's Turkey Nest Survival and Factors Affecting Nest Predation by Mammals

Nest success is an important parameter affecting population fluctuations of wild turkeys (Meleagris gallopavo). Factors influencing mammalian predation on turkey nests are complicated and not well understood. Therefore, we assessed nest hazard risk by testing competing hypotheses of Merriam's turkey (M.g. merriami) nest survival in a ponderosa pine (Pinus ponderosa) ecosystem during 2001-2003. We collected nesting information on 83 female Merriam's turkeys; annual nest success averaged 50% for adult females (range 45-59%) and 83% for yearling females (range 75-100%). Proportional hazard modeling indicated that precipitation increased the hazard of nest mortality. However, estimated hazard of nest predation was lowered when incubating females had greater shrub cover and visual obstruction around nests. Coyotes (Canis latrans) were the primary predator on turkey nests. We hypothesize that precipitation is the best predictor of nest survival for first nests because coyotes use olfaction effectively to find nesting females during wet periods. Temporally, as the nesting season progressed, precipitation declined and vegetation cover increased and coyotes may have more difficulty detecting nests under these conditions later in the nesting period. The interaction of concealment cover with precipitation indicated that nest hazard risk from daily precipitation was reduced with greater shrub cover. Management activities that promote greater shrub cover may partially offset the negative effects of greater precipitation events. (JOURNAL OF WILDLIFE MANAGEMENT 72(8): 1765-1774; 2008)