R.B. Woosnam was the leader of the British Museum Expedition to the Ruwenzori Mountains in present Uganda. Subsequently he wrote a paper on "Ruwenzori and its life zones" (Geographical Journal, 1907) in which he identified six vegetation zones running concentrically rould the ridge at altitudes from below 2000 meters to above 5100 meters. In 1910 he was appointed chief game ranger of British East Africa.
Around this time Woosnam travelled to Ngamiland (now part of eastern Botswana) and other parts of southern Africa to collect natural history specimens for the British Museum (Natural History) and the Zoological Society of London. A list of the mammals he obtained during the expedition, with field notes by the collector, was published by G. Dollman in the Annals and Magazine of Natural History in 1910. His itinerary and field notes on the birds of Ngamiland were published by W.R. Ogilvie-Grant in The Ibis in 1912.