Austin Roberts, ornithologist and mammalogist, was the son of Archdeacon Alfred Roberts and his wife, the naturalist and artist Marianne Edwardine (Edda) Fannin*. Noel Roberts* was his elder brother. Their mother no doubt engendered in her sons an interest in the natural world. Austin received most of his early education from his father while the family resided at Lydenburg. In 1891 they moved to Potchefstroom and while at school there he came in contact with the naturalist Thomas Ayres*, who taught him to skin birds and small mammals and to record information about every specimen accurately, and encouraged him to study birds systematically. Just before the outbreak of the Anglo-Boer War (1899-1902) the two brothers and their mother moved to a family farm in Natal, returning to Potchefstroom in 1901. Austin became a clerk at the local branch of Standard Bank until July 1903, when he was employed in the civil service of the Transvaal Colony. During the next two years he worked in the Department of Inland Revenue in Potchefstroom, Pretoria and Wolmaranstad, but lost his position when he failed the qualifying departmental examination. He then became a temporary clerk in the Unpaid Salaries Commission, Pretoria, until April 1906, when he enlisted as a trooper in Royston's Horse during the Bambatha Rebellion in Natal. After being demobilised in August that year he and his brother Noel collected birds' eggs and nests which they presented to the Transvaal Museum, Pretoria. He worked as a temporary clerk in the Department of Agriculture until December 1907 and then joined the Natal Militia Force as a trooper. During these years he devoted all his spare time to natural history. His first scientific publication, "Visit to a colony of Ibis aethiopica", appeared in the Journal of the South African Ornithologists' Union in 1905 and was followed regularly by further papers.
From April to November 1908 Roberts accompanied Frederick V. Kirby* on his expedition to the Quelimane district of Mozambique to destroy lions for the Boror Company, which had extensive coffee and sugar plantations there. He collected 340 bird skins and a number of small mammals, which he sold to the Transvaal Museum. Shortly after his return from Mozambique he fell ill with blackwater fever and after more than a year of financial hardship finally realised his ideal of employment as a naturalist. In September 1910 he was appointed as temporary zoological assistant at the Transvaal Museum, then directed by Dr J.W.B. Gunning*. After three years of uncertainty and low remuneration he received a permanent appointment and was put in charge of the museum's bird and mammal collections in the Department of Higher Vertebrates. In May 1914 he married Dora S. Cooper (born Barrett), with whom he had three sons and a daughter. During World War I (1914-1918) he served first as a trooper in German East Africa and later as a gunner with the South African Field Artillery in Palestine.
Roberts remained at the Transvaal Museum for 38 years, and it seems that his lack of formal education retarded both his professional advancement and recognition. He built up the museum's collections to over 30 000 birds and some 13 000 mammals, then the largest and most representative such collections in the country. This was achieved by means of many extensive collecting expeditions all over southern Africa, including a trip to Southern Rhodesia (now Zimbabwe, 1914), the Vernay-Lang Kalahari Expedition (1930), the Barlow Expedition to South West Africa (now Namibia) and the Northern Cape (1937), and another trip to these same regions in 1941. He was an excellent field naturalist who compiled detailed notes on his field observations and gained an extensive knowledge of the behaviour and life histories of birds and mammals. His collections also included some internal and external parasites, fungi, and other plants. Many of the specimens were prepared by him personally. His field work formed the basis of his detailed documentation of southern African birds and mammals. In the course of his career he described and named 429 bird taxa and 406 mammal taxa. This vast output was partly the result of his approach to taxonomy as a "splitter" - quick to create a new genus, species or subspecies on the basis of slight differences. He defended this approach vigorously in his "Review of the nomenclature of South African birds" (Annals of the Transvaal Museum, 1922), in which he proposed over 100 new genera. It earned him considerable criticism from other systematists, and the vast majority of these new genera were not accepted. However, his taxonomic work was based on vast field experience and though many of his proposed species and subspecies have also not stood the test of time, he came to be regarded eventually as the greatest authority on both South African birds and mammals.
Roberts described his specimens and observations of birds and mammals in over a hundred papers in the Annals of the Transvaal Museum, Journal of the South African Ornithologists' Union, The Ostrich and elsewhere, adding greatly to existing knowledge. His paper on "The grass warblers of South Africa" (Annals of the Transvaal Museum, 1913, 40p), for example, has been described as an admirable review and put the classification of the South African members of this group on a sound basis for the first time. His "Synoptic check list of the birds of South Africa" (Ibid, 1924, 107p), with keys to the genera and species, was a useful tool for taxonomists. Later he wrote an important guidebook, The birds of South Africa (London, 1940), with plates painted by Norman C.K. Lighton. This book was the first really comprehensive work on the subject. It proved a scientific best-seller and inspired a love of birds among numerous people in southern Africa. It was subsequently revised and expanded by various experts and published in a number of later editions.
Roberts similarly gave much attention to mammals. In a paper on "New forms of African mammals" (Annals of the Transvaal Museum, 1929) he described no less than 45 new species and sub-species, mostly from South Africa. After completing his bird book he turned his attention to his second major ambition, namely the compilation of a comprehensive book on mammals. The manuscript was more or less completed at the time of his death in 1948. It was subsequently edited by R. Bigalke, V.F. Fitzsimons and D.E. Malan and published as The mammals of South Africa (Johannesburg, 1951, 701p), with plates painted by Reverend Pierre J. Smit*. At the time of his death Roberts had started to expand his bird book into a handbook that would cover all current knowledge, but had completed only the part dealing with sea birds. His vision of such a work was eventually realised by the publication of Roberts birds of southern Africa (7th ed., 2005, 1296p), edited by P.A.R. Hocky, W.R.J. Dean and P.G. Ryan.
In spite of his limited formal education Roberts became an eminent scientist through persistent effort. He was an unassuming and dedicated researcher, always ready to assist other naturalists. Imbued with a high sense of integrity, he sometimes appeared to hold uncompromising attitudes in defence of his principles. The government of South Africa recognised his expertise as a mammalogist when bubonic plague broke out in the Free State in 1920. He was seconded to the Department of Health for three months to help determine which rodent species harboured the disease. Over the next few years more outbreaks occurred and he was again called upon. During 1925 and 1927 he delivered over 100 public lectures in affected areas for the Department of Health, to explain the precautions to be taken against the spread of the disease.
Roberts played an active part in the affairs of several scientific societies. In 1904 he became a foundation member of the South African Ornithologists Union. He was also a foundation member, and honorary secretary for 1915, of the Transvaal Biological Society. When these two societies amalgamated in 1916 to form the South African Biological Society he automatically became a foundation member of the latter. Over the years he delivered many talks before its members and was elected its president for 1933. He was a member also of the Transvaal Game Protection Society, later the Wild Life Protection Society of South Africa, serving as a member of council of the latter. In 1929 he helped to found the South African Ornithological Society, served as its honorary secretary for several years, and was elected an honorary life member in 1939. As a member of the South African Association for the Advancement of Science from 1915 he served on its council and was elected president of Section D (which included zoology) for 1936/7. He was a foundation member of the South African Museums Association in 1937, served on its council, and was elected president for 1944/5. He was a charter member of the American Society of Mammalogists from its foundation in 1919, an Empire member of the British Ornithologists' Union from 1930, a corresponding member of the Bavarian Ornithological Society from 1922, and a corresponding member of the Zoological Society of London from 1934.
His contributions to science were recognised by several societies and institutions. In 1934 a grant from the Carnegie Foundation enabled him to visit museums and other institutions in Britain and the United States. The University of Pretoria awarded him an honorary Doctor of Science (DSc) degree in 1935. He was awarded the Senior Captain Scott Memorial Medal of the South African Biological Society in 1938 and the South Africa Medal (gold) of the South African Associatio for the Advancement of Science in 1940. Early in 1948 he was offered the post of curator of the Queen Victoria Museum in Harare, but his death prevented him from taking up the position. The Austin Roberts Bird Sanctuary in Pretoria was named in his honour in 1956 and he is commemorated in the name of Roberts's Warbler, Oreophilais robertsi. The flowering plants he collected are in the National Herbarium, Pretoria, while his fungi went to the National Collection of Fungi at the Plant Protection Research Institute in Pretoria.