This fourth and final volume of the series on Seabird Colonies of British Columbia considers all known seabird colonies in the BC portion of the Salish Sea, from the north end of the Strait of Georgia to Victoria at the south end of Vancouver Island. The Salish Sea area is heavily urbanized, with some of the most rapidly expanding human populations in Canada exerting tremendous and increasing pressure on the environment. This volume is intended as an aid to the conservation and management of nesting seabirds and the marine ecosystems they depend on in this intensely developed region.

The volume presents the status and historical changes of seabird breeding populations at all known breeding sites, including in urban areas, which have become important habitats and now support large proportions of the seabird breeding community in the Salish Sea. Colony histories, regional summaries, and in-depth analyses of population trends for the 10 colonial-nesting seabird species that have been recorded breeding in the Salish Sea are presented, current through 2023 Introductory sections describe persons and institutions that have contributed to our knowledge of seabird breeding populations in the area. Historical impacts and current threats to nesting populations and established and recommended conservation measures are reviewed.

In addition to presenting data current through 2023 for the Salish Sea colonies, an appendix to this fourth volume also updates, to 2023, population estimates and trends for all colonies on the BC coast. Tables in Appendix 1 provide updated population estimates for every known current and historical colony site in Haida Gwaii and the BC Outer Coast areas that were addressed in volumes 2 and 3 of this series. Summary statistics for the entire coast are also presented, updating to 2023 the provincial summaries present in volume 1.

As with previous volumes, this final volume is lavishly illustrated with hundreds of photographs, now presented in full colour, and is peppered with anecdotes that recount experiences of the authors and others and relate interesting details and musings about seabird natural history and conservation. Numerous people generously contributed many wonderful photographs and anecdotes, and lovely paintings and drawings have again been contributed by renowned local artists.

This volume continues the decades-long commitment of authors Michael Rodway, Wayne Campbell, and Moira Lemon to promote the conservation of breeding seabirds in BC. Combined, they have over 130 years of seabird experience and have visited all colonies in British Columbia at least once and some many times.

The book is entirely a volunteer effort. Its publication is supported by the non-profit Biodiversity Centre for Wildlife Studies located in Victoria, British Columbia and by the Canadian Wildlife Service of Environment and Climate Change Canada. More information can be found on the Biodiversity Centre for Wildlife Studies