The geographic distribution and populations of cliff-nesting seabirds are essential elements in the assessment of their ecological roles and status. Here, a geographic mapping approach was used to visualize the biogeography of European seabirds. This approach was conducted at two temporally separated time intervals: 2004–2010 was compared to 1982–1988. Three biogeographic regions were identified: Arctic, Boreal and Ibero-Atlantic. The data show that species richness has remained stable over the approximately 20-year interval, as have, in general, population numbers and geographic distribution. Such stability, compared to recent declining trends worldwide, may be due to earlier human-driven declines in the European Atlantic, followed by effective conservation measures for the remaining populations. The species richness of cliff-nesting seabirds may not be principally determined by island area and distance from a large land mass, but rather by the extent of vertical cliff façade and distance from fishing areas. The stable species richness of each European Atlantic geographical sub-unit suggests that not only individual islands and mainland but rather the entire European Atlantic functions as a single large “cliff seabird island” in determining biogeographic seabird equilibrium.