My granddaughter was very keen on the extensive Animal Ark series, quite realistic stories about children and animals in different settings and countries.
I've only actually read a few but one was about children discovering poachers in Africa and helping to get them arrested. I found it both gripping and informative.
Classics like Black Beauty, Charlotte's Web perhaps. Michael Morpurgo's Farm Boy, several others by him maybe.
The Once and Future King by TB White has a fascinating, realistic scene in which the young hero is changed into a bird of prey. Lovely description from the bird's point of view.
Librarians and bookshop personnel will, in my experience, be pleased to advise you too.