Castle Rock Seabird Project

Window's Media Player See real time video of seabirds at Castle Rock
(requires Windows Media Player to view)
For updates and more information, click here.

Second largest seabird nesting site in the California Current.
Second largest seabird nesting site in the California Current.

The Biological Importance of Castle Rock

Castle Rock a 14-acre island located less than 2 miles off the coast of Crescent City, California.  A part of the National Wildlife Refuge System, Castle Rock is the second largest seabird breeding colony along the California coast, hosting more than 100,000 birds.  Twelve different species are known to have nested on this island including common murre, cormorants, pigeon guillemots, Cassin’s auklets, rhinoceros auklets, and storm petrels.

Scope and Importance of the Castle Rock Project

This project is designed to study the abundance and health of the populations of seabirds nesting on Castle Rock.  While some species like common murres nest on rock ledges and can be observed through aerial photography; other species, such as rhinoceros auklets, Cassin’s auklets, and leach’s storm petrels, are nocturnal and burrow into the soft soil making aerial observation impossible.  These burrowing species can make tunnels up to six-feet long, into the soft and fragile ground.  Any human disturbance on the surface can simply and easily crush and destroy the underground nest of these seabirds. 

Soils on the island are fragile and can collapse on burrow nests as this deep footprint in the soft soil shows.
Soils on the island are fragile and can collapse on burrow nests as this deep footprint in the soft soil shows.

The challenge of this project is to develop a way to study the seabird colony without disturbing the birds or crushing burrow nests.  By using video cameras as a remote sensing technique the biologists are able to gather data on relative abundance, burrow use, attendance and departure, nesting chronologies, and breeding behavior of seabirds species on Castle Rock.

Understanding the biology of these seabirds is important to the conservation of the species.  As the second largest breeding colony in California, Castle Rock is a vital link in the health of these populations.  These birds forage in the ocean and also reflect the ocean condition.

Video Link

Due to damage to the antenna on 3 May 2006, video quality has been compromised. Although the video is not as good as before 3 May, it is still viewable. We are working on solutions.

Window's Media Player See real time video of seabirds at Castle Rock. (requires Windows Media Player to view)

Although the video is active 24 hours, seven days a week, access via this link will be restricted to daylight hours.  Equipment on the mainland makes detailed recordings of all activities on Castle Rock.  Video equipment is in part built by See More Wildlife Systems in Alaska.

Where is Castle Rock?

Public access to the island is restricted because of fragile soils and the disturbance caused by humans to birds and marine mammals; however Castle Rock can be viewed from Pebble Beach Drive in Crescent City (see map).  Close-up views of the birds on the island are now available through real-time video which can be viewed through the link on this website or web connections on the Humboldt State University campus.  Direct video (high quality) is accessible to the public at the Crescent City visitor center of the National Park Service (1111 Second Street, Crescent City, CA). 

Biologists reach the island by helicopter
Biologists reach the island by helicopter


Castle Rock National Wildlife Refuge is managed by Humboldt Bay National Wildlife Refuge.  The project is a cooperative effort of Humboldt State University, the U.S. Fish and Wildlife Service (Humboldt Bay NWR and San Francisco Bay NWR), the National Park Service (Redwood National and State Parks), and the U.S. Coast Guard (Air Station Humboldt Bay).  Funding was provided by the Coastal Program at Humboldt Bay, U.S. Fish and Wildlife Service, Humboldt State University, and the U.S. Geological Survey.

Rocky outcrops and fragile soils on Castle Rock
Rocky outcrops and fragile soils on Castle Rock


Inquiries about this project should be directed to either

Dr. Rick Golightly
Dept. of Wildlife
Humboldt State University
Arcata, CA 95521

Mr. Eric Nelson
Humboldt Bay National
Wildlife Refuge
1020 Ranch Rd
Loleta, CA 95551-9633

Bird List

Common Birds on Castle Rock that you may see in the video include the following:

Common Murre
Pigeon Guillemot
Brandt’s Cormorant
Pelagic Cormorant
Double-crested Cormorant

Tufted Puffin
Rhinoceros Auklet
Cassinís Auklet
Leachís Storm-Petrel

Fork-tailed Storm-Petrel
Western Gull
Peregrine Falcon
Black Oystercatcher