Roy Brown & John Ferguson 
Tracks and Signs of the Birds of Britain and Europe [EPUB ebook] 

Featuring updated data for this second edition, this is a field guide
to the tracks and signs of European birds. It describes, with colour
illustrations, the many physical signs that can be found in the field.
From feathers and skulls to prey remains and pellets, the volume seeks
to enable the field ornithologist to establish the presence of a
species without necessarily ever encountering the bird itself. Using
the information provided, readers should be able to learn much about
their local birds” habitat use and lifestyles. This edition includes
ten new plates of artwork, and covers a number of new species.