Understanding how the distribution and abundance of food resources influence space use of organisms is an important element of successful conservation and recovery strategies for endangered species. We investigated interrelationships between space use, activity patterns, and food resources for lesser long-nosed bats (Leptonycteris curasoae), an endangered nectar-feeding bat, during an energetically demanding phase of its annual life cycle. We estimated the size of home ranges (95% kernel areas) and core use-areas (50% kernel areas) of bats and estimated density of their forage plant (Agave palmeri) in and near these use areas. Density (x̄± SE plants/ha) of flowering agaves within home ranges (3.6 ± 1.04) exceeded that which was available on the landscape (1.8 ± 0.36), indicating that bats selected areas with high food abundance. Although density of agaves within home ranges of bats differed in successive years (1998: 3.6 ± 1.04; 1999: 0.8 ± 0.15), sizes of home ranges and core use-areas of adult bats were similar between years, suggesting that the relationship between home-range size and density of food resources was mediated by other factors. Differences in activity budgets of bats between years suggest that bats altered their behavior in response to changes in food abundance, allocating more time to foraging the year fewer flowering plants were present. Consequently, reductions in agave density could increase energy demands of foraging bats and reduce the chances of successful recovery of lesser long-nosed bat populations.