№ 172
Manx Shearwater
Puffinus puffinus
Comes ashore only after dark, and about a third of the world's population nests on Rùm. The story goes that Norse sailors took the calls for trolls, and a peak there is still called Trollaval.
Photo · Martin Reith · CC BY-SA 3.0 · source · Wikimedia Commons. Cropped and resized.
Call · Sean Morris · CC BY-NC-SA 4.0 · source · xeno-canto. Trimmed to 30 seconds, volume normalised.