When it comes to remembering where a tasty titbit was left, female great tit birds are miles ahead of their male counterparts. This ability might have evolved because the females come second when theres food to be shared, argue Anders Brodin and Utku Urhan of Lund University in Sweden. In Springers journal Behavioral Ecology and Sociobiology, they present one of only a handful of cases in nature in which the female of a bird species has better spatial1 and learning abilities than the male. Great tits are highly intelligent and quick learners. These common European songbirds have interesting and ever-changing ways in which they find food, and even use tools such as conifer needles during foraging2. Unlike most other members of the tit family, great tits are not food hoarders. Brodin and Urhan have previously3 demonstrated that they are able to observe where their hoarding4 relatives have made a stash5, only to retrieve6 it up to 24 hours later.To test if there are any gender7 differences in this ability, Brodin and Urhan first allowed caged great tits to observe marsh8 tits store away food in an indoor aviary9. One hour later, great tits of both sexes were released to search for the cached food. The females performed consistently better than males in this memorization task. Male great tits were able to remember where other birds stored food only in 15 percent of the cases. In contrast, the females remembered positions of cached food in 40 percent of the cases. For Brodin and Urhan, this is a remarkable10 achievement, as the success rate of the females equals the performance of marsh tits and other birds that retrieve their own caches. This suggests that female great tits recover caches they have watched others make as successfully as the hoarders retrieve their own stash.The researchers argue that female great tits are more skilled cache pilferers because they find themselves in a male-dominated society in which they are often pushed away from available food sources.Whereas the males therefore have a more even and reliable food supply, lower-ranking females have to supplement their food by pilfering11 the stock piles of others, argues Brodin. Therefore a good memory of where caches are to be found could go a long way to still their hunger.Such ability could also be helpful to the female birds in a broader sense, elaborates Urhan. Females could choose to ignore pieces of food they find when a male is nearby. If she returns later when the male is not close, she decreases the risk of getting the food item stolen by the male.
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1 spatial adj.空间的，占据空间的 参考例句： This part of brain judges the spatial relationship between objects.大脑的这部分判断物体间的空间关系。 They said that time is the feeling of spatial displacement.他们说时间是空间位移的感觉。
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