Performance of four seed-caching corvid species in the radial-arm maze analog.

Four seed-caching corvid species were tested in an open-room analog of the radial-arm maze. During Experiment 1, the species more dependent on stored food. Clark's nutcrackers (Nucifraga columbiana) and pinyon jays (Gymnorhinus cyanocephalus), acquired the task more quickly and to higher accuracy levels than either scrub jays (Aphelocoma coerulescens) or Mexican jays (A. ultramarina). During Experiment 2, performance after retention intervals was tested. When intervals of 30-210 min were tested in ascending order, species differences observed during acquisition were again obtained. However, when intervals of 5-300 min were tested in random order, the species differed only at shorter intervals. During Experiment 3, only nutcrackers gave any indication of performing above chance after a 24-hr retention intervals. Results support the hypothesis of species differences in spatial information processing that correlate with dependence on stored food.