Data from: Female cowbirds have more accurate spatial memory than males

Brown-headed cowbirds (Molothrus ater) are obligate brood parasites. Only females search for host nests and they find host nests one or more days before placing eggs in them. Past work has shown that females have a larger hippocampus than males, but sex differences in spatial cognition have not been extensively investigated. We tested cowbirds for sex and seasonal differences in spatial memory on a foraging task with an ecologically relevant retention interval. Birds were trained to find one rewarded location among 25 after 24 h. Females made significantly fewer errors than males and took more direct paths to the rewarded location than males. Females and males showed similar search times, indicating there was no sex difference in motivation. This sex difference in spatial cognition is the reverse of that observed in some polygynous mammals and is consistent with the hypothesis that spatial cognition is adaptively specialized in this brood-parasitic species.棕头牛鹂（Molothrus ater）为专性巢寄生鸟类。仅雌性个体负责搜寻寄主巢穴，且会在产卵前1天或多天提前定位到寄主巢穴。既往研究表明雌性个体的海马体（hippocampus）较雄性更大，但空间认知层面的性别差异尚未得到广泛深入的探究。本研究采用与生态场景适配的延迟间隔范式，通过觅食任务检测棕头牛鹂在空间记忆上的性别与季节差异：实验对象需经过训练，在24小时后从25个候选位置中找到曾被赋予奖励的目标位置。结果显示，雌性个体的犯错次数显著少于雄性，且前往目标奖励位置的路径更具直达性；雌雄个体的搜索时长无显著差异，表明二者的实验动机不存在性别差异。本次观测到的空间认知性别差异与部分多配制哺乳动物的相关研究结果恰好相反，这一发现支持了"空间认知在该巢寄生物种中存在适应性特化"的假说。