Spanish Silbo, a whistle language, has only four vowel and four consonant sounds. Audible for miles, it resembles bird calls.

西班牙的席尔波语是一种口哨语言，只有四个元音和四个辅音。几英里外都能听到它的声音，它就像鸟儿的鸣叫。

youdao

Hundreds of birds fly in a sunny blue sky. The only sounds are bird calls and the soft noise made by tall grasses as the water slowly moves them.

无数的鸟在阳光明媚的蓝天中飞翔，这里你只能听到鸟的叫声以及当水流缓慢流经草的时候，这些草所发出的柔和的声音。

youdao

A little bird comes out at every hour and calls the time.

每小时有一只小鸟跑出来报时。

youdao

Along with the flapping, the robotic bird included a small sound generating system to play authentic calls and swamp noises.

ENGADGET: Alt-week 3.2.13: A mission to Mars, robosparrow and facial recognition in fertility treatment

If the caxirola follows the fate of the vuvuzela or rattle, Brazil has a Plan B involving the production of a plastic version of the indigenous pedhua whistle, which mimics bird calls.

CNN: Brazil unveils shaky answer to the vuvuzela for World Cup

Early-bird optimists bought August 5 strike calls, which would require a 25% jump in the space of the coming two weeks.

FORBES: Magazine Article