These changes, which gave birds greater facility for flight, made them more effective predators. It's not difficult to imagine that they feasted on giant insects.
这些变化明显增强了鸟类的飞行能力，进而提高了它们的捕食效率。不难想象，他们开始将大型昆虫作为猎捕目标。
That's one theory, at least. Another holds that rather than eat giant insects, prehistoric birds simply out competed them. Both birds and giant insects ate smaller insects that existed alongside their super-sized cousins. Evolution may have enabled birds not only to dine on giant insects but also to consume smaller insects and deplete their competitors' food source.
至少，这是其中的一项理论。另一种理论认为，与其说史前鸟类以巨型昆虫为食，不如说其淘汰掉了巨型昆虫。鸟类和巨型昆虫均以较小昆虫为食，而小型昆虫的栖息地又临近大型昆虫。进化后的鸟类不仅能够捕食巨型昆虫，同时还能捕食小型昆虫，从而消耗竞争对手——巨型昆虫的食物来源。
