Birdsong and Spectrograms

I came across a fascinating YouTube video exploring the acoustics of birdsong.

The creator uses spectrograms to break down the incredible vocal mechanics birds use to produce complex sounds. One of the most interesting parts is where he synthesizes a sound that encodes an image of a bird into its spectrogram (reminiscent of that famous Aphex Twin spectrogram Easter egg), only to discover that certain bird vocalizations naturally form recognizable visual shapes when visualized as sound waves. Very weird, but remarkably cool.