The song of the Snipe is made by two vibrating feathers in its tail, captured brilliantly by Tim Melling in the image above.
And Tim wrote of the discovery of this phenomenon in a blog a couple of years ago:
During the early years of the twentieth century debate raged as to whether this sound was produced vocally or mechanically as wind rushed past the outer tail feathers.
The conundrum of how the sound was produced was finally laid to rest at a British Ornithologists’ Club dinner in 1931 when Sir Philip Manson-Bahr twirled a cork with snipe feathers on a string around his head and reproduced the humming sound. This was in the very public Pagani’s Restaurant in London and apparently the whole room resonated to the sound of a drumming Snipe. Others had suggested it was the tail feathers that produced the sound much earlier but it was Manson-Bahr’s theatrical demonstration that finally convinced all doubters. So the humming noise is produced by air whizzing past the outer tail feathers but the vibrato is produced by the wings flapping and varying the air flow across the tail feathers.https://markavery.info/2018/06/02/tim-melling-drumming-snipe/
Here is what the ‘song’ sounds like. First a recording from Germany;
… and a Polish bird:
… and a UK bird from Scotland:
Amazing isn’t it?