Seed preferences and foraging by granivores at raccoon latrines in the transmission dynamics of the raccoon roundworm (Baylisascaris procyonis)

Raccoons (Procyon lotor) habitually defecate at preferred sites (latrines). Feces at latrines often harbor eggs of the roundworm Baylisascaris procyon is, a parasite of raccoons that is pathogenic to numerous species of small vertebrates. Undigested seeds are also commonly found in raccoon feces, the composition varying with availability of seed types. Thus, feces at latrin es may serve as a source of food and pose a mortality risk for small graniv ores. To examine this interaction, we manipulated the seed composition in f eces at simulated raccoon latrines and tested for differences in vertebrate visitation rates as a function of seed type. Treatments involved placing s eeds, including corn, cherry ( Prunus virginiana), dogwood (Cornus racemosa ), and a combination of the three types, at simulated raccoon latrines. Usi ng Trailmaster(TM) camera systems we documented 2406 vertebrate visits by 1 6 mammal and 11 bird species during 455 camera-nights. Small granivorous ma mmals, including white-footed mice (Peromyscus leucopus) and eastern chipmu nks (Tamias striatus), were the most common visitors. Visitation by white-f ooted mice was significantly greater when corn, the most preferred seed typ e, was present in raccoon feces. Visitation by eastern chipmunks and other vertebrate species did not vary with seed type. Active foraging was documen ted for five vertebrate species and accounted for 10% of all recorded event s. We conclude that raccoon latrines are routinely visited by a variety of vertebrate species, especially small granivores. Active foraging for seeds in raccoon feces is an important risk factor for transmission of B. procyon is to small vertebrates, and white-footed mice may suffer elevated rates of infection when corn is present in raccoon feces.