Seasonal Foods of Blacktail Jackrabbits and Nuttall Cottontails in Southeastern Idaho

Abstract

The diets of blacktail jackrabbits (Lepus californicus) and nuttall cottontails (Sylvilagus nuttalli) were estimated by examination of fecal pellet botanical composition. The deficiencies of fecal analysis are noted, but dietary trends and relative importance of forage plants are accurate. Cluster analysis combined leporid pellets into 2 distinct groups based on botanical composition, representing feeding during spring-summer and fall-winter periods. Seven variables (plant species) accounted for significant differences (P<0.05) within and among the leporids studied in seasonal food selection. Generally, grasses and forbs were most abundant in blacktail jackrabbit and nuttall cottontail pellets during the spring-summer period, whereas shrubs were most abundant during the fall-winter period. Diet similarity was greatest between blacktail jackrabbits and nuttall cottontails during the same season. Diversity of forage consumed was greatest for both leporids during spring-summer periods. Habitat segregation minimizes competition for forage between the leporids studied. Livestock grazing appears to limit leporid population density rather than alter leporid food habits.