Habitat Use by Nesting Grassland Birds and Their Snake Predators in the Tallgrass Prairie

Grassland bird populations have seen greater declines than any other group of birds in North America. Although snake predation is considered the primary reason for nest failure, little is known about how management practices in the Flint Hills region of Kansas impact movement and habitat use of snakes, and the predator-prey interaction between snakes and nests of grassland birds. Radio telemetry was used to study habitat use, considering 11 habitat variables, of 6 Eastern Racers (Coluber constrictor) and 9 Great Plains Rat Snakes (Elaphe emoryi). Grassland bird nests were monitored, including 84 nests that were eventually predated and 37 nests that fledged. After nesting was complete, a similar habitat analysis was conducted. Nest monitoring results showed snakes accounting for up to 72% of all nest failures; however, the rate of snake predation depended on land management techniques. The average daily nest survival rate was 90.03%, or a total survival rate of 12.98%. Several habitat characteristics including percent coverage by shrubs and grass were important in distinguishing among the habitats of the four groups. Fledged nests were found in habitats with sparser vegetation and more rocks than predated nests. Predated nests and both snake species shared habitats, but fledged nests were located in significantly different habitats from the other three groups. Thus, land management practices that manipulate habitat structure may directly influence grassland bird nest success by altering snake predation risk.