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.
Prema Davidu Attenboroughu i nekim drugim ljudima i ptice to rade -- ptice među krošnjama, gdje je lišće gusto, glasaju se uglavnom visoko, kratko i ponavljajući se.