As a naturalist and ornithologist, Eyton was a life-long friend of Charles Darwin, with whom he had studied at Cambridge University. He was also friends with ornithologist John Gould.

From an early age Eyton published articles on plants, cattle, fish and birds. He was particularly interested in birds; one of his first large-scale books was ‘A Monograph of the Anatidae, or Duck Tribe’ (1838), primarily illustrated by Edward Lear.

Eyton also published works on the plants and animals of his native Shropshire and the surrounding area. He was a keen collector of animal skins and skeletons, and when he inherited his father’s estate, Eyton Hall in 1855 he built a museum there to contain it.

Eyton also collected natural history prints and drawings. His friend and fellow ornithologist William Jardine recorded a shopping trip to London in which Eyton bought ‘prints and boxes of them by the hundred’. John Ruskin bought this collection of around 7000 illustrations in 1880 for Sheffield's Ruskin Collection.