Using the term "bird brain" is one way to insult another person's intelligence. That is because a bird's brain is small. So, anyone with such a bird-sized brain was thought to be not that intelligent.
使用bird brain这个措辞是侮辱另一个人智商的一种方式。这是因为鸟的大脑很小，所以脑袋跟鸟一样大的人被认为不那么聪明。

But calling someone a bird brain might not be as insulting as it once was.
但是称某人是bird brain可能不像以前那般侮辱人了。

That finding comes from a study of the mental abilities of birds.
这一发现源自一项鸟类心智能力的研究。

Two European scientists reported that at least two kinds of birds -- crows and parrots -- can think logically. A crow or parrot can recognize itself when the bird sees its image in a mirror.
两名欧洲科学家报告称，至少乌鸦和鹦鹉这两种鸟类可以合乎逻辑地思考。乌鸦或鹦鹉在镜子中看到自己的影像时可以认出自己。

The scientists say crows and parrots also can feel empathy. In other words, they are able to understand and share the experiences and emotions of other birds.
科学家们表示，乌鸦和鹦鹉还能产生情感共鸣。换句话说，它们能够理解并分享其它鸟的经验和情绪。

According to researchers, these abilities are "as sophisticated and diverse as those of apes."
根据研究人员的说法，它们的这些能力同类人猿一样的复杂和多样化。

However, the brains of birds and those of apes are different. The brain of a bird does not have a neocortex. The neocortex controls thinking and remembering -- one's cognitive skills. A bird brain is also much smaller than the brain of a monkey or other ape.
然而，鸟类和类人猿的大脑是不同的。鸟类大脑不具备大脑皮层。大脑皮层控制着思维和记忆这种认知能力。鸟类大脑同样也比猴子以及类人猿的大脑要小得多。

So how can birds perform as well as mammals in some activities?
那么鸟类在一些行为上如何能跟哺乳动物一样做呢？

Researchers in Germany suggest that different methods of complex thinking developed independently in birds and mammals.
德国研究人员提出，鸟类和哺乳动物各自发展出了不同的综合思维方式。

The researchers found that the brains of birds and mammals do have different structures. But there are also similarities in the brain architecture.
研究人员发现，鸟类和哺乳动物确实有着不同的大脑组织。但是在大脑结构上有相似之处。

The brains of both creatures have what is called a pre-frontal structure that controls similar high-level functions. The researchers propose a separate path of development for the similarities. The reason: both species faced the same challenges for survival.
这两种动物的大脑都有着所谓控制高级功能的前额叶结构。研究人员提出，这种相似性有着各自独立的发展路径。原因是因为这两个物种都面临着同样的生存挑战。

The researchers noted that neither a multilayered cortex nor a big brain is required for complex mental skills. They reported their findings in the journal Trends in Cognitive Sciences.
研究人员指出，无论是多层化的大脑皮质，还是大大的脑袋，这都不是复杂心智技能所需的。他们在《认知科学趋势》杂志上发表了他们的研究结果。