This post was contributed by Chet Ogan, a retired wildlife biologist who was involved with the original WHSRN application for Humboldt Bay in 1998. He continues to be involved with the Redwood Region Audubon Society.
New Shorebird Numbers Result in a WHSRN Site Upgrade
Humboldt Bay Complex in northwestern California was accepted as a Western Hemisphere Shorebird Reserve Network (WHSRN) Site of International Importance in 1998. The designation was based on the overwintering shorebird population exceeding 100,000 birds from 34 species. This 19,500-hectare site is the northernmost wintering area for significant numbers of Long-billed Curlews, Marbled Godwits, and Willets. Humboldt Bay Complex also serves as a staging area for up to 30,000 Pacific Brant and over 100,000 Aleutian Cackling Geese. Pacific Brant graze on eelgrass prior to migration north to Alaska, and at low tides the eelgrass beds are used by shorebirds foraging for invertebrates.
It had been suspected that shorebird numbers were underestimated, so in 2018 Redwood Region Audubon and California Audubon helped fund a shorebird count by Dr. Mark Colwell at Humboldt State University. He trained a team of experienced birders and they tallied over 500,000 shorebirds at Humboldt Bay Complex, many of them Western Sandpipers. Based on this new shorebird study, Dr. Colwell requested an upgrade of the Humboldt site to one of Hemispheric Importance, which was granted by the WHSRN board. Humboldt Bay is also designated as an Important Bird Area of global significance.
Even with these important designations–neither of which offer regulatory power–Humboldt Bay's habitats are vulnerable. The eelgrass beds so critical to Pacific Brant are also preferred sites for oyster cultivation, which can degrade the beds. Future additional concerns for the site will be related to climate change, as well as industrial development and increased human population. Since the Humboldt Bay Complex was established as a WHSRN site several significant things have happened, among them the expansion of Humboldt Bay National Wildlife Refuge, wetland acquisition, and restoration of saltmarshes around the bay. But continued research, effective conservation actions and advocacy are still needed to keep the birds at Humboldt thriving.
