Blair had an interest in natural history which stemmed from his childhood. In letters from school he wrote about caterpillars and butterflies, and Buddicom recalls his keen interest in ornithology. He also enjoyed fishing and shooting rabbits, and conducting experiments as in cooking a hedgehog or shooting down a jackdaw from the Eton roof to dissect it. His zeal for scientific experiments extended to explosives—again Buddicom recalls a cook giving notice because of the noise. Later in Southwold, his sister Avril recalled him blowing up the garden. When teaching he enthused his students with his nature-rambles both at Southwold and at Hayes. His adult diaries are permeated with his observations on nature.