harry was the second surviving son of henry forbes witherby (1836–1907) of holmehurst, burley, hants, a law stationer employing 169 men who retired from the family business in 1899 to focus on his interests in painting and ornithology, leaving it to be run by his sons. after leaving school witherby entered the old family publishing firm of witherby and co, from which he retired in 1936, but resumed work again after the outbreak of the second world war. the family firm of h f and g witherby, originally printers, began to publish bird books early in the 20th century. from an early age witherby devoted himself to the study of ornithology, travelling extensively, including visits to iran, the kola peninsula, and the white nile. he described the latter in his book "bird hunting on the white nile" (1902). he married lilian gillson in 1904. lilian joined him on his travels and even learnt to skin birds on their honeymoon. they had two sons and three daughters.