Samuel D. Bairstow, son of George Bairstow and his wife Hannah, came to South Africa around 1880 and was a resident of Port Elizabeth and vicinity to his death in 1898. He was a businessman connected with the wool trade and a partner in the merchant firm Longworth & Bairstow of Port Elizabeth, but an active natural historian in his spare time. Before coming to South Africa he had already been a contributor to Miss E.A. Ormerod's* annual British reports, Observations on injurious insects. In 1885 he asked Miss Ormerod if she would compile a book on the insect pests of the Cape if he sent her the necessary notes. This she agreed to, and Bairstow provided both notes and specimens for the book, which was published as Notes and descriptions of a few injurious farm and fruit insects of South Africa (London, 1889). Around the same time Roland Trimen* of the South African Museum, Cape Town, acknowledged him in the preface to his book, South African butterflies... (1887-1889) as a contributor of butterflies from the Port Elizabeth region.
During the early eighteen-nineties Bairstow was a consulting entomologist to the Department of Agriculture of the Cape Colony and was supplied with a microscope and other equipment for his entomological studies, his main service being the publication of articles on insect pests in the Agricultural Journal of the Cape Colony. These included contributions on the codling moth, fruit fly and brown locust (1892, Vol. 2, pp. 160-162, 180-182), "The philosophy of entomology" (1895, Vol. 8, pp. 152-3), and "The golden washed carrot and turnip moth" (1895, Vol. 8, p. 357).
Dr S. Schonland*, Director of the Albany Museum, described Bairstow as a keen observer of nature and a discriminating collector to whom the Albany Museum owed a great many valuable specimens and who would especially be remembered for his studies in economic entomology. According to Schonland it was Bairstow "who gave this country its first glimpse of hope" when the Australian bug, the scale insect Icerya purchasi, threatened to destroy the Cape orange groves and other trees and shrubs. He found [as had entomologists investigating the problem in Australia in 1885] that an Australian ladybird species, the vedalia beetle Rodolia iceryae (now Rodolia cardinalis) was a natural enemy of the Australian bug and could keep it under control.
Bairstow's second main interest was shell collecting and he is regarded as the doyen among the shell-collecting fraternity of the Eastern Cape during the eighteen-eighties. He described the natural history of Algoa Bay in his extensive "Natural history notes from South Africa" in The Naturalist in 1883, and in 1888 donated a collection of 1000 shell specimens from Port Alfred to the Port Elizabeth Museum. A collection of his shells was examined by G.B. Sowerby* in 1892 and afterwards presented to the University of Oxford Museum. He discovered many new species, and those named in his honour include Marginella bairstowi, Conus bairstowi, and Dolocholatirus bairstowi. Unfortunately some foreign shells without location data in his collection were recorded by Sowerby* as South African, to the detriment of both their reputations.
Bairstow was a fellow of the Linnaean Society and was active in several local scientific organisations. He was a founding member and honorary secretary of the Port Elizabeth Naturalists' Society (1882-1884), and several times exhibited insects at its meetings. In 1884 the society changed its name to the Eastenr Province Naturalists' Society, with Bairstow continuing to act as secretary to May 1885. One of his lectures to members, "Are the lower animals endowed with reason?" (April 1884) dealt with his observations on the problem solving behaviour of caterpillars in escaping from artificial confinement. In 1886/7 he was president of the society. In 1888, when Port Elizabeth started its own museum (with many specimens taken over from the old museum of the Port Elizabeth Athenaeum), Bairstow served on its first management committee. In 1891 he was also a member of the management committee of the Albany Museum. By 1895 he had moved to the Suurberg (north of Port Elizabeth), where he spent the last few years of his life in a sanatorium. He was married to Helena Marion Bairstow, with whom he had four children.