Printed

Animal Tracks and Signsby Preben Bang & Preben Dahlstrøm (OUP Oxford 2006)

Bats by Dean Waters & Ruth Warren (Mammal Society 2009)

Collins Complete British Animals by Paul Sterry (Collins  2010)

Mammals of the British Isles; Handbookby S. Harris & D.W. Yalden (Mammal Society 4th edition, 2008)

Websites

Google Lens: Go to google.com and there is a camera icon at the right of the search bar. Click on this, and you can drag and drop any image and it will do its best to identify it – so can be used for any flora and fauna, vertebrates and invertebrates etc. (as well as buildings, landscapes – anything, in fact.)  Worth a look, but treat identifications with caution!

Apps