His work in ornithology took him to Central America to study indigenous birds, Midway atoll to study seabird nesting energetics, as well as South Africa to study the sociable weaver. His most important contributions were in studying thermoregulation in birds, which he frequently accomplished in the hot deserts of North Africa. The Auk cites his study on Egyptian plovers as the most important of those works, discovering that the birds carry water in their feathers to transfer to the sand around their buried eggs to keep them cool in the desert heat. His studies in Central America were his other main body of work, especially in Nicaragua. Between 1951 and 1967 he repeatedly visited Nicaragua, resulting in improvements to the taxonomy of birds in Adriaan Joseph van Rossem's collection, and the discovery of a number of atypically small subspecies of temperate zone birds.
