John Gerrard Keulemans was the most sought-after bird artist of the late 19th and early 20th centuries. A prolific, talented, work-oriented illustrator, he produced quantities of excellent bird plates for books and journals of the period. Although he worked largely from bird specimens, he was adept at creating drawings that were anatomically correct as well as attractively presented.

Keulemans was one of several well-known artists who contributed to Lord Thomas Lilford's Coloured Figures of the Birds of the British Islands (1885-1897). This seven-volume work contained 421 plates, representing late 19th-century chromo lithography at its best. He illustrated many important bird books, including Buller's A History of the Birds of New Zealand, 1873 - 1888, William Vincent Legge's History of the Birds of Ceylon, 1880, Richard Bowdler Sharpe's Monograph of the Alcedinidae (kingfishers), 1868, Henry Seebohm's Monograph of the Turdidae (thrushes),1902, Osbert Salvin's Biologia Centrali-Americana (1879-1904), Edgar Leopold Layard's Birds of South Africa (1887) and Henry Eeles Dresser's History of the Birds of Europe.

In 2012 Te papa Press announced a landmark publication titled Buller's Birds of New Zealand: The complete work of JG Keulemans by author Geoff Norman. The publication was awarded NZ Herald Book of the Year in December 2012.