What is the theme in Birds, Beasts, and Relatives by Gerald Durrell?

A love of nature is the main theme of the book. Gerald's love of nature and natural history are at the heart of almost every endeavor and escapade in which he's involved. This love of nature is so complete that Gerald spends hours seeking out answers on his own and is most interested in those adults who can further his education on this point. For example, Gerald spends hours watching the dung beetles he finds in the garden of their rented villa. The dedication required for a ten-year-old boy to spend hours patiently waiting for a pair of beetles to complete their journey is incredible in itself, but Gerald's reaction when he discovers that the beetles take the ball of dung underground is also an indication of his dedication to learning.