Long-term spatial memory in four seed-caching corvid species

Clark's nutcrackers, Nucifraga columbiana, pinyon jays, Gymnorhinus cyanocephalus, scrub-jays, Aphelocoma coerulescens, and Mexican jays, A. ultramarina, differ in their dependence on cached seeds in their natural environments. The hypothesis that these species differ in their long-term ability to remember the locations of caches was tested in the laboratory. Birds recovered caches 10, 60, 150 and 250 days after making them. All species performed at levels better than chance overall, but scrub-jays and Mexican jays performed with modest accuracy at all time intervals. Nutcrackers and pinyon jays performed very accurately with 10- and 60-day intervals but not after longer intervals. These results corroborate the species differences in spatial memory that have been observed in previous studies. The performance of scrub- and Mexican jays can, however, be interpreted either as the rapid forgetting of most information or as the long-term retention of a small amount of information. Therefore it cannot be concluded that these four species differ in their long-term spatial memory abilities. (C) 1997 The Association for the Study of Animal Behaviour.