USE OF SIMULATED HERBACEOUS CANOPY BY FORAGING RODENTS

Use of seeds from simulated herbaceous canopy by western harvest mice (Reithrodontomys megalotis), deer mice (Peromyscus maniculatus) and wh ite-footed mice (Peromyscus leucopus) was examined in laboratory trial s. Each mouse was tested on both simulated full-moon and new-moon nigh ts but with only one of three abundances of surface seeds (high, low o r zero abundances of seeds in trays on arena floor). White-footed mice ate more total seeds (surface plus canopy seeds) during dark-bright t han bright-dark trials and with high than lo-iv or zero abundances of surface seeds. However, neither the order of dark and bright condition s nor availability of surface seeds influenced total seeds eaten by de er mice and harvest mice. All three species readily foraged in the can opy in the absence of surface seeds (>90% of trials on both dark and b right nights). When surface seeds were abundant, interspecific differe nces in canopy foraging were evident as canopy foraging occurred durin g 54% of trials on both dark and bright nights for harvest mice, 58% a nd 21% of trials on dark and bright nights, respectively, for white-fo oted mice and 8% and 0% of trials on dark and bright nights for deer m ice.