Few scientists have combined the skills of mathematics and biology to open new fields of knowledge the way Robert H. MacArthur did in his pioneering work in evolutionary ecology. Guided by a wide-ranging curiosity for all things natural, MacArthur had a special interest in birds and much of his work dealt primarily with bird populations. His conclusions, however, were not specific to ornithology but transformed both population biology and biogeography in general.

Robert Helmer MacArthur was born in Toronto, Ontario, Canada, on April 7, 1930, the youngest son of John Wood and Olive (Turner) MacArthur. While Robert spent his first seventeen years attending public schools in Toronto, his father shuttled between the University of Toronto and Marlboro College in Marlboro, Vermont, as a professor of genetics. Robert MacArthur graduated from high school in 1947 and immediately immigrated...