In 1907, aged seventeen, he joined the Royal Australasian Ornithologists Union and during the next year wrote six articles in the organisation's journal, the Emu.
In the Maryborough and Dunolly Advertiser he campaigned in 1908 against the killing of egrets for feathers for women's hats, a crusade in which he won support from Australian poet Dame Mary Gilmore.
By this time, his own health was in serious decline, although he continued living alone in a small flat in Sydney's Cremorne Point until his death in 1977.
Visiting England in 1938, Chisholm discovered a large number of documents relating to the nineteenth-century ornithologist John Gould.
They included the diary kept by Gould's principal collector, John Gilbert, during his participation in Ludwig Leichhardt’s 1844-45 expedition to Port Essington.