This is Scientific American — 60-Second Science. I'm Christopher Intagliata.
The old expression "bird brain," referring to a small or inadequate brain size—it's not all that accurate. Take crows, for example, and other corvids, like jays and magpies. "Many corvids have relatively large brains for their body size, and can do amazing things." Anders Møller, an evolutionary biologist at the French National Science Research Council. "So this 'bird brain' expression is a little bit simplified." Some birds are so intelligent that they're informally referred to as "primates with feathers."
But even among the smartest bird species, there's still natural variation in brain size. Which is a big deal—when it comes to being hunted. Møller worked with a taxidermy shop in Denmark, which had data on nearly 4000 birds brought in to be stuffed since 1960. A lot of the birds were just found dead—hit a window or wire—and people picked them up. But 300 of the specimens had been hunted.
So Møller's team then compared the brain sizes of birds that got shot to those that didn't. They controlled for the birds' age, sex, body size, and species. And they found that the hunted specimens' brains were actually five percent smaller, on average, than the brains of birds that died by other means. "The surprising thing is that, if you make a similar kind of analysis of liver or heart size, there is absolutely no difference there. So this is specific to the brain." The results are in the journal Biology Letters.
The researchers assume that individuals with larger brains had what they called "superior escape ability." That is, they were better at not getting shot.
As game season begins, Møller has this observation for hunters: "When you are sitting at the dinner table and eating the duck that you managed to shoot, with all likelihood it's one with a disproportionately small brain." Most certainly food for thought.
Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata.
俗语“鸟的大脑”指的是大脑尺寸较小或不足，但这并完全不正确 。以乌鸦、松鸦和喜鹊等其他鸦科鸟类为例 。“与体型相比，许多鸦科鸟类的大脑尺寸较大，而且这些鸦科鸟类可以做出令人吃惊的事情 。”安德斯·莫勒是法国国家科学研究委员会的进化生物学家 。“所以，‘鸟的大脑'这种表述有些简单化了 。”有些鸟类非常聪明，所以它们被人类称为“长着羽毛的灵长类动物” 。
但是，即使是最聪明的鸟类，它们的大脑尺寸也存在自然变化 。这在鸟类被猎杀时是个非常重要的问题 。莫勒和丹麦的一家标本店进行了合作，这家标本店里有1960年以来近4000只鸟类的标本数据 。在这些标本中，有很多鸟被发现时已经死亡，它们可能因为撞到窗户或是电线而死亡，人们只是把它们收集了起来 。但是其中有300个鸟类标本是通过猎杀制作的 。
莫勒的团队将被射杀鸟类的大脑尺寸和未被射杀鸟类的大脑进行了比较 。他们限定了鸟类的年龄、性别、体型以及物种 。他们发现，平均来说，被猎杀标本的大脑尺寸比因其他原因死亡的鸟类小百分之五 。“令人惊讶的是，如果对肝脏或者心脏的尺寸进行类似分析，会发现尺寸没有任何的区别 。所以，只有大脑才会有尺寸的区别 。”该研究结果发表在《生物学快报》期刊上 。
研究人员认为，拥有较大尺寸大脑的个体具有“出众的逃生能力” 。也就是说，它们能更好地躲避射杀 。
捕猎季即将开始，莫勒对捕猎者说：“当你坐在餐桌旁享用你捕到的鸭子时，那很可能是一只大脑比较小的鸭子 。”这的确是引人思考的事情 。
谢谢大家收听科学美国人——60秒科学 。我是克里斯托弗·因塔利亚塔 。
1. when it comes to 谈到；涉及；
例句：You may not be weak, but when it comes to money, you get wimpy.
2. pick up 拿起；提起；拾起；捡起；
例句：She stooped to pick up a piece of paper.
3. on average 平均起来；按平均值；
例句：On average, she said, women do two-thirds of the housework and three-fourths of the child care.
4. manage to do sth. 设法做到；成功完成；
例句：I wonder how he could manage to possess himself of that secret.