Jerdon started collecting birds almost immediately on arrival in India on 21 February 1836. He sent his collections of birds collected during his early travels to
William Jardine for identification, but by the time they arrived at Jardine's house in
Scotland they had become infested by moths. Jerdon trusted his own identifications from then on, publishing
A Catalogue of the Birds of the Indian Peninsula for the
Madras Journal of Literature and Science (1839–40). This included 420 species, almost doubling the list produced earlier by
Colonel W. H. Sykes. The want of brief, but comprehensive Manual of the Natural History of India has been long felt by all interested in such inquiries. At the present, it is necessary to search through voluminous transactions of learned Societies, and scientific Journals, to obtain any general acquaintance with what has been already ascertained regarding the
Fauna of India, and, excepting to a few more favorably placed, even these are inaccessible. The issue of a Manual, which should comprise all available information in sufficient detail for the discrimination and identification of such objects of Natural History as might be met with, without being rendered cumbrous by minutiae of synonymy or of history, has therefore long been considered a desideratum. To meet this want it is proposed to publish a series of such Manuals for all the Vertebrated Animals of India, containing characters of all the classes, orders, families, and genera, and descriptions of all the species of all Mammals, Birds, Reptiles, and Fishes, found in India. Prospectus in his Birds of India regarding the proposed
The Fauna of British India, Including Ceylon and Burma. Jerdon's most important publication was
The Birds of India (1862–64), which included over 1008 species Jerdon's opinion on Darwin's theory was that it "
perhaps, lays too much stress on external and fortuitous circumstances as producing varieties, and not enough on the inherent power of change." The reviewer also pointed out problems in his usage of
George Gray's arrangement of the bird classes and states: "
In thus following the phantasies of Kaup, and the mad vagaries of Bonaparte (in his latest writings), we cannot believe that Dr. Jerdon has acted well for his own reputation, nor wisely as regards the class of readers for whom his volumes are specially intended." Jerdon documented the local names of many birds although he did not follow a consistent spelling for Hindi and Urdu words. Jerdon's other major work was the
Illustrations of Indian Ornithology in 1844, which included illustration made by Indian artists (some from Trichinopoly), about which he wrote in his later works: '' Other works included
The Game Birds and Wildfowl of India (1864) and
Mammals of India (1874). He had a wide interest in natural history and his studies include descriptions of plants, ants, amphibians, reptiles, birds as well as mammals. Jerdon was instrumental in the birth of
The Fauna of British India, Including Ceylon and Burma series. The need for a work on the Indian fauna was felt and it was finally approved by the Secretary of state and was placed under the editorship of
W. T. Blanford.
R. A. Sterndale mentions a note from Jerdon on an otter that he kept as a pet (probably at Tellicherry) His work on the reptiles of India was not completed and it was only after his death that the proofs were sent to his home. In 1874 several volumes with his original drawings of reptiles were auctioned by Messrs. Sotheby, Wilkinson and Hodge. Some of these illustrations were purchased by
Lord Lilford. Apart from zoology, he also took an interest in botany, although he did not publish on the topic and instead communicated notes to botanists such as
Robert Wight. Wight notes that: ==Eponyms==