[1] In 1972 he accepted an invitation to join the staff of the Durban Natural Science Museum, aware that he needed to obtain a higher degree, either a master's or a doctorate, to maintain the position.
His submitted thesis was queried by a prominent United States ornithologist who offered to assist him in working on it.
Later, in particular after he joined the Percy FitzPatrick Institute, he widened his field of expertise, especially regarding the taxonomy and other biological aspects of various seabird groups.
One of his major works is the "South African red data book – birds", for which he was awarded the Gill Memorial Medal.
[1] One of his last papers reflect his findings on the possible difference of the South African pied avocet, which he thought was a distinct subspecies.