Ecologists are beginning to appreciate the complex energetic links between aquatic and terrestrial systems (Baxter et al. 2005). It has been estimated that in some riparian systems, 25-100% of the energy and carbon budgets of terrestrial birds, bats, lizards, and spiders can be derived from aquatic insects. Most studies of energy and nutrient fluxes from aquatic to terrestrial ecosystems have focused on the smaller insectivorous passerine birds (reviewed by Baxter et al. 2005). Our focus is on the importance of insects, specifically the California Stonefly (Pteronarcys californica), in the diet of the Peregrine Falcon (Falco peregrinus).