David Brewer was born in Worcestershire, England. He read Natural Sciences at Cambridge and received his PhD, in Heterocyclic Chemistry, from Glasgow, Scotland. After a fellowship at the University of Arizona, Tucson, he emigrated to Canada where he worked as an industrial research chemist. He started bird watching at the age of eleven, and backyard bird ringing at fourteen.

He has watched birds on all seven continents, but his main area interests are the study and conservation of birds of South and Central America, and also bird banding. His publications include Wrens, Dippers and Thrashers (Helm, 2001), Where to Watch Birds in Central America and the Caribbean (with Nigel Wheatley), (Helm, 2002), the four-volume Canadian Atlas of Bird Banding (Canadian Wildlife Service, 2001-2010), and contributions to three volumes of the Handbook of the Birds of the World (Lynx, 2005–2010). He has, for more than twenty-five years, been a Research Associate in Ornithology from the Royal Ontario Museum, Toronto.