He also conducted research on natural history and breeding behavior of the Kirtland's warbler (and other avian species) from the early 1950s through the end of 1963.
In 1964 he accepted an invitation to spend the spring semester as guest professor at the University of Hawaii-Manoa, and in 1965, after spending a year teaching and doing research at the University of Baroda (India), he returned to Hawaii and served two terms as the Chairman of the UH-Manoa Zoology Department.
Although his early interests included the morphology, behavior and classification of birds from the cuckoo family, from 1965 onward he specialized in researching and documenting the history and living conditions of the endemic avian species of the Hawaiian islands.
He often spoke out against various state government agencies and related special interest groups when they advocated policies that threatened the survival of rare and endangered species.
He also wrote books on avian and human anatomy, and also an article from 1957 where he describes the extinct Bourbon crested starling and its relationship to other bird families.