This monograph is a revision and updating of our publication on the birds of Brier Island, Nova Scotia, published in the Proceedings of the Nova Scotian Institute of Science in 2011. Known for its concentrations of seabirds and large volume of migration in spring and autumn, the island has gained constantly increasing attention by birders since it was first investigated by members of the Nova Scotia Bird Society in 1955. The past decade, since 2011, has seen a remarkable increase in bird reports, mainly due to increased field work by birders, but also because of the use of the online bird logging system eBird. The heart of this monograph is the annotated list of birds, which has been enlarged and revised in the light of new reports by field observers and new information from the ornithological literature. We have incorporated eBird observations, along with our personal records of occurrences and bird banding data into this revision, along with the changes in the order and arrangement of North American bird families as set out by the Checklist Committee of the American Ornithological Society. Three species, Pacific Golden-Plover, Brown Booby and Zone-tailed Hawk, have been added to the island checklist, and one has been lost, Thayer’s Gull, which has been incorporated into Iceland Gull. The total list of species reported from the island is 357, including two hypothetical species. The number of known breeding bird species has increased from 74 to 83. We also update ecological knowledge of the island as a result of recent fieldwork and the restoration of the Big Meadow Bog in support of Eastern Mountain Avens conservation.