Birds Britannica is a book by Mark Cocker and Richard Mabey,[1] about the birds of the United Kingdom, and a sister volume to Mabey's 1996[2] Flora Britannica,[1][2] about British plants.

[2] According to the project's official website:[1] It covers cultural links; social history; birds as food; ecology; the lore and language of birds; myths, art, literature and music; anecdotes, birdsong and rare facts; modern developments; migration, the seasons and our sense of place.Over 1,000 members of the public provided details of their observations and experiences,[1] during the book's eight-year[1] research period.

Mabey's contribution was limited by his depression,[2] leading to Cocker having a leading role, doing the bulk of the work[3] and this more prominent credit.

The Guardian described the book as "a glorious encyclopedia"[2] and Cocker as "British bird life's perfect encyclopedist".

[2] The Times said "The entries for every species are a fascinating distillation of expert knowledge, personal account, reminiscence, literary reference and folk belief".