|Wildlife and Habitat: Humboldt Bay is a biologically rich area, hosting especially large populations of water birds due to the extensive eelgrass beds and mudflats in the area. During the winter, more than 100,000 birds will use the bay as a feeding and resting site. The area is critical for migrating Aleutian Canada geese (upwards of 20,000 will use the bay each year) and black brant (Humboldt Bay is considered the most important area south of Alaska for this species). Other common bird species on the bay are willets, marbled godwits, dunlin, least and western sandpipers, cormorants, wigeon, greater scaup, bufflehead, surf and white-winged scoters, green-winged teal, pintail, great and snowy egrets, and great blue heron.
Humboldt Bay’s eelgrass beds, the largest south of Washington’s Willapa Bay, also make the area an important spawning, brooding, and feeding area for fish and other marine species, including steelhead trout, Coho and Chinook Salmon, harbor seals, northern elephant seals, California sea lions, and Stellar’s sea lions. A number of threatened and endangered species call the bay home, including peregrine falcons, bald eagles, brown pelicans, western snowy plovers, Humboldt Bay wallflowers, and beach layia.
The refuge’s other two units, Lanphere Dunes and Castle Rock, are also important coastal habitats. The Lanphere Dunes Unit protects the most pristine remaining coastal dunes in the Pacific Northwest. The 14-acre Castle Rock island, located 1 mile off the coast near Crescent City, is one of the West coast’s most important seabird nesting colonies and hosts California’s largest population of breeding common murres.