The naturalist was born in Alnwick and succeeded to the Twizell estate in 1804. He became High Sheriff of Northumberland in 1823. He produced Illustrations of British Ornithology (1821-34) in nineteen volumes, the first book of British birds to be shown life-size. This was followed by Illustrations of Ornithology (1825-43) with Sir William Jardine to which he contributed volumes on the Pigeons and the Parrots in 1834 and 1836, the latter illustrated by Edward Lear. A History of British Forest Trees was published in 1842.
Selby is buried at Bamburgh. In 1885 his collections were sold and dispersed. Twizell House, a splendid building by Wyatt, was demolished in 1950.