What are the most common descriptors found in the common names for birds found in Britain? Species names according to the British Ornithologists' Union's "The British List" - https://bou.org.uk/wp-content/uploads/2016/07/British-List.pdf
E.g. "Great Northern Diver" = "Great" and "Northern"
Adjectives in the bird's name do not count, for example, a "Common Yellowthroat" only gives you "Common", but a "Common Yellow-Throated Bird" gives you "Common", "Yellow", and "Throated"