Charles F.M. Swynnerton, naturalist, was the son of Reverend Charles Swynnerton and his wife Maude Massey. He was educated in England at Lancing College (in Lancing, just west of Brighton), and showed an early interest in natural history. He came to Natal in 1897, at the age of 19. There he met the British businessman and naturalist Guy A.K. Marshall* and accompanied him to Salisbury (now Harare, Zimbabwe) where he worked in Marshall's trading store. In 1898 he became manager of a farm (now in Mozambique) near Melsetter, a region then known as Gazaland. In 1900 he became manager of the nearby Gungunyana farm, in the Chipinge district, which Marshall had just bought. This farm was a naturalist's haven and included part of the Mount Selinda forest. Here Swynnerton experimented with crops and trees. He was the first to grow coffee in the area, but coffee leaf disease proved uncontrollable. He was more successful with ceara rubber, though falling prices made the crop uneconomic. Other experiments by him involved reafforestation with both indigenous and exotic trees after forest fires. In 1908 he married Nora A.G. Smyth, with whom he had three sons.
In addition to farming Swynnerton made extensive collections of birds, insects and plants. His large collections of plants, including some fungi and lichens, were described in a monograph by A.B. Rendle and others, "A contribution to our knowledge of the flora of Gazaland; being an account of the collections made by C.F.M. Swynnerton", in the Journal of the Linnean Society (Botany) (1911, 245p). He investigated mimicry in butterflies and recorded some of his results in 1915 and 1919. In his research on aposematic butterflies (those with coloration to warn or repel predators) he was the first to record that birds may vomit if they eat unpallatable butterflies of the family Danaidae and that they try to dissuade their fledglings from preying on members of this family. Several papers by him dealt with birds. In two of these, each in two parts, he described the birds of Gazaland (The Ibis, 1907, 1908) and in another the birds of Mount Chirinda (The Ibis, 1911). These papers contained many notes on the stomach contents of insectivorous birds. Three other papers in the same journal dealt with the significance of the colours of birds' eggs and mouths, and the rejection of eggs not matching those of the nest owner. With D.P.J. Odendaal he published "On some nests and eggs from Mount Chirinda, Southern Rhodesia" in the Journal of the South African Ornithologists' Union (1911).
Swynnerton was a member of the Rhodesia Scientific Association and in June 1910 addressed its members on "Fauna, flora and products of the Melsetter District...". He was a member also of the South African Ornithologists' Union, serving as joint vice-president from 1911 to 1916. When the Union amalgamated with the Transvaal Biological Society in 1916 to form the South African Biological Society he was elected joint vice-presidents of the latter for 1917 to 1919. He was elected a Fellow of the Linnean Society in 1907 and by 1918 was a Fellow also of the Royal Entomological Society and the Royal Horticultural Society. He became a member of the South African Association for the Advancement of Science in 1915 and contributed a paper on "Some factors in the replacement of the ancient East African forest by wooded pasture land" to its Report for 1917. In 1913 he bought the farm "Confidence" near Chipinge and in 1921 also acquired most of Gungunyana from Marshall.
In 1918 the government of Southern Rhodesia (now Zimbabwe) commissioned him to study the distribution of tsetse fly and later that year the government of Mozambique asked him to extend his investigation to that territory. He studied the distribution and density of the various species of tsetse flies in relation to the vegetation which sheltered them and reported his findings in "An examination of the Tsetse problem in North Mossurize, Portuguese East Africa" (Bulletin of Entomological Research, 1920-1921). This work led to his appointment in 1919 as the first game warden of Tanganyika (now Tanzania), his main task being to investigate tsetse fly. At the request of the South African government he visited Zululand in 1923 in connection with the tsetse problem. In 1929 he was appointed as the first director of the Department of Tsetse Research at Shinyanga, Tanzania. He published a monumental monograph on the work of his department carried out between January 1931 and December 1934, entitled The tsetse flies of East Africa; a first study of their ecology, with a view to their control (London, 1936, 579p plus maps and figures). Other publications by him included a Report on the control of elephants in Uganda (Entebe, 1924, 24p), and a paper on a new coffee plant, "A new coffea from Portuguese East Africa, with ecological notes on the genus" (with R. Philipson, Journal of Botany, 1936).
Swynnerton was one of the great naturalists of southern Africa. He had immense enthusiasm, an excellent memory, and a devotion to scientific accuracy. The British government honoured him as a Companion of the Order of St Michael and St George (CMG) in 1938, but on his way to Dar es Salaam to receive this honour he was killed when his plane crashed in the Singida district of Tanzania. He was survived by his wife and three sons. His Gazaland bird collections were sent to the Natural History Museum in London and contained many new forms. The bird genus Swynnertonia, containing only Swynnertonia swynnertoni (Swynnerton's Robin), still commemorates him, as did several other species or subspecies. Also named after him were the plant genus Swynnertonia and more than 40 plant species, including Aloe swynnertonii and Erica swynnertonii. His plant specimens went to the herbaria at the Natural History Museum (London), Kew Gardens, and the Botanischer Museum in Berlin-Dalheim, Germany. Other species named after him include a tsetse fly of the genus Glossina and several butterflies.