birdsong

Without a doubt, you would find it dull at first the loudest sound is usually birdsong.

毫无疑问，一开始你会发现它的声音很沉闷，最大声的声音通常是鸟鸣声。

The air is filled with birdsong.

处处闻啼鸟。

Take a drink outside with a good person, a good gathering: talk with the sun and the wind with birdsong for the background.

和好朋友在外面喝一杯，好好聚一次：谈天论地，以鸟声做伴。

The evidence suggests that warblers use their extremely elaborate songs primarily to attract females, clearly confirming the effect of intersexual selection on the evolution of birdsong.

证据表明，莺主要用它们极其精致的歌声吸引雌性，这清楚地证实了雌雄间选择对鸟类鸣叫进化的影响。

Birdsong has also kept his promise.

伯德桑也遵守了他的诺言。