Well, according to David Attenborough and some other people, birds do it too -- that the birds in the canopy, where the foliage is dense, their calls tend to be high-pitched, short and repetitive.
根据大卫·爱登堡（David Attenborough，著名生物纪录片主持人）和其他人所说 鸟儿们也是这么做的 树冠上的鸟 在树枝浓密的地方 它们的叫声通常 调子更高，急促，反复