The ‘greater male variability hypothesis’ predicts that males exhibit larger ranges of variation in cognitive performance compared to females, however, support for this hypothesis has come exclusively from studies of humans. This scenario aligns with the fact that the vast majority of the literature assessing sex differences in cognition is based on studies of humans and a few other mammals. In order to elucidate the underpinnings of cognitive variation and the potential for fitness consequences, we must investigate sex differences in cognition in non-mammalian systems as well. Here we assess the performance of male and female food-caching birds on a spatial learning and memory task and a reversal spatial task to address whether there are sex differences in mean cognitive performance or in the range of variation in performance. For both tasks, male and female mean performance was similar across four years of testing; however, males did exhibit a wider range of variation in performance on the reversal spatial task compared to females. The implications for mate choice and sexual selection of cognitive abilities are discussed, with a call for further investigation into sex-related cognitive variation.