Castle Rock National Wildlife Refuge
Eighty miles north of Humboldt Bay, Castle Rock National Wildlife Refuge (NWR) lies about a half mile offshore from Crescent City, California. Castle Rock NWR is only 14 acres in size, but is critical to the survival of several hundred thousand seabirds each year. It is also a key roost site for up to 20,000 Aleutian cackling geese each winter and spring.
Castle Rock NWR is closed to the public to prevent disturbance to the seabirds, their habitat, and marine mammals. The birds of Castle Rock can best be seen in the early morning hours with a spotting scope from Pebble Beach Drive.
From February to mid-April, the dawn fly-off of Aleutian cackling geese from Castle Rock is often spectacular. The geese roost on Castle Rock each night and feed on mainland pastures by day.
Castle Rock rises 335 feet above sea level with a grassy slope, two large inlets, and cliffs that are important to nesting seabirds in the summer.
The cliffs provide nesting habitat for one of the largest breeding populations (100,000) of common murres on the Pacific coast. Ten other species of seabirds also nest here, including three species of cormorants, pigeon guillemots, Cassin’s and rhinoceros auklets, Leach’s and fork-tailed storm-petrels, and tufted puffins. Because many of these bird species nest in burrows and crevices and are primarily nocturnal, they avoid predation by western gulls that also nest on the island.
Castle Rock NWR also serves as an important haul out (resting site) for marine mammals, including harbor seals, northern elephant seals (both bear pups there), and California and Steller sea lions.
Castle Rock was purchased in 1979 from The Nature Conservancy.