Some food-storing animals use spatial memory in food retrieval. There is variation amongst food-storing species in the duration over which food is stored and it is positively correlated with differences in the size of the part of the brain that is involved with memory for storage locations, the hippocampus. For example, British marsh tits (Parus palustris) are generally thought to retrieve their stores after a few hours or days whereas Scandinavian willow tits (P. montanus) have been shown to store their food for several weeks to months. Marsh tits also have a smaller hippocampus than do willow tits. This experiment tested the hypothesis that retrieval success (and thus memory capacity) of the two species differs depending on the usual length of time for which food is stored. Individuals of both species were tested on their ability to retrieve five stored food items after two differing delays: 2-3 h ('short') and 17 days ('long'). The prediction was that there would be no differences in retrieval performance between the species after the short delay but that willow tits would be more accurate at retrieving their stores than marsh tits after the long delay. The results did not provide support for this hypothesis as there were no differences between the species in retrieval performance following either delay: both species successfully retrieved food after both delays.