Humboldt Bay, California is more important to spring migrating shorebirds than previously recognized

An important first step in conservation is recognition of critical habitats worthy of protection. Both the Ramsar Convention and Western Hemisphere Shorebird Reserve Network (WHSRN) gauge wetland importance based on total shorebird abundance or percentage of a flyway population using a site. In 1998, WHSRN designated Humboldt Bay, California, USA a site of International Importance based on estimated use by >100,000 shorebirds. Here, we provide data from a recent survey effort to show that the bay and surrounding habitats are used by >500,000 shorebirds of ~26 species during spring migration alone; most observations were of Western Sandpipers Calidris mauri. These data indicate that Humboldt Bay, at least in some years, is more important than previously recognized and, therefore, worthy of elevated WHSRN status as a Hemispheric site.