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Humboldt Bay Complex

Site Facts

Country, State, Province/Region:

United States, California

Relative Location:

Northwestern California, Humboldt County by the cities of Arcata and Eureka.


40º 45’ N 124º 13’ W



Basis for Designation:

Usage by over 100,000 shorebirds


19,500 ha (48,186 acres)


September 1998

Site Owner/Steward:

U.S. Fish & Wildlife Service, California Department of Fish & Game, Bureau of Land Management, City of Arcata

Site Partners:

Humboldt State University, California Northcoast Chapter of The Wildlife Society , Humboldt Bay National Wildlife Refuge

Human Population within 100 km:

approx. 70,000


Chet Ogan
Research Technician-Wildlife
Redwood Sciences Laboratory USFS



Habitat Description

The Humboldt Bay WHSRN complex contains the largest bay between San Francisco and Coos Bay, Oregon and the delta wetlands of three rivers, the Eel, Elk, and Mad. There is a rich diversity of habitat types including invertebrate rich tidal mudflats, eelgrass beds, salt marsh, estuarine, riverine, and palustrine wetlands, dunes, and seasonally flooded agricultural fields which covers an area over 75 square miles (195 square kilometers). Eighteen square miles (47 square kilometers) has refuge status under the US Fish and Wildlife Service or California Department of Fish and Game. Other key landowners include the Bureau of Land Management, the Humboldt Bay Harbor, Recreation and Conservation District, and the Cities of Arcata and Eureka. The eelgrass beds in the bay are the largest between Willapa Bay, WA, and Baja California, Mexico, and provide cover for many species of marine and estuarine vertebrates and invertebratesand food for hundreds of thousands of migrating shorebirds and waterfowl, especially Pacific Brant.

Land Use
Most of South Humboldt Bay is under USFWS jurisdiction while areas around North Humboldt Bay are owned by California Department of Fish and Game, City of Arcata, and USFWS. The Nature Conservancy has given their land to Humboldt Bay NWR. The central channel between the bays lies within the jurisdiction of the City of Eureka and is predominately industrial and urban. In 2004 the area was designated as an Important Bird Area by National Audubon Society.

Eureka on Humboldt Bay continues to be a hub of commerce for the local area. The Old Town area has many beautiful Victorian homes and businesses including the world famous Carson Mansion. Timber industry is still very important to the area as well as fishing. The Port of Humboldt Bay is closer to the Orient than Portland, Oregon, or San Francisco so there is pressure to entice trans-oceanic shippers to our area. While this would be a boon to our local economy, risks would come with more pressure for development and from exotic organisms that could be introduced into Humboldt Bay. Soil disturbance caused by logging, road building, and development on local watersheds continue to be a source of sedimentation and turbidity on Humboldt Bay.

Conservation and Ecology


Over 230 species of birds have been found within the Humboldt Bay Complex including over 31 species of waterfowl numbering approximately 70,000 throughout the winter. The over wintering shorebird population exceeds 100,000 birds from 34 species. This site is the northernmost wintering area for significant numbers of Long-billed Curlews, Marbled Godwits, and Willets. Over a million shorebirds migrate through the Humboldt Bay area. Humboldt Bay Harbor Conservation and Recreation District has many beautiful pictures and lists of local flora and fauna.

Shorebirds seen annually at the site:

  • Black-bellied Plover
  • Pacific Golden-Plover
  • Snowy Plover
  • Semipalmated Plover
  • Killdeer
  • Black Oystercatcher
  • Black-necked Stilt
  • American Avocet
  • Greater Yellowlegs
  • Lesser Yellowlegs
  • Solitary Sandpiper
  • Willet
  • Wandering Tattler
  • Spotted sandpiper
  • Whimbrel
  • Long-billed Curlew
  • Marbled Godwit
  • Ruddy Turnstone
  • Black Turnstone
  • Surfbird
  • Red Knot
  • Sanderling
  • Semipalmated Sandpiper
  • Western Sandpiper
  • Least Sandpiper
  • Baird’s Sandpiper
  • Pectoral Sandpiper
  • Rock Sandpiper
  • Dunlin
  • Ruff
  • Short-billed Dowitcher
  • Long-billed Dowitcher
  • Wilson’s Snipe
  • Red Phalarope

Other wildlife

  • Aleutian Cackling Goose- winter foraging and roosting, the population locally exceeds 40,000 Aleutian Cackling geese; the Humboldt Bay region is becoming more important for this species
  • Pacific Brant- critical winter/spring migration and staging area that supports >50% of the entire flyway population annually 
  • Black Brant- critical winter migration staging area and winter foraging area
  • Bald Eagle- winter (Nov-Mar) foraging and local nesting now occurring
  • Peregrine Falcon- foraging throughout the area
  • Brown pelican (Aug-October) - foraging in tidal wetlands and estuaries; roosting on sand bars and islands
  • Snowy Plover- A management plan is currently being adopted to protect nests on gravel bars and sand dunes within the area
  • Tidewater goby- bays and tidal ponds
  • Green Sturgeon- bays and channels
  • Salmonid species- Steelhead, Coastal Cutthroat, Coho Salmon, Sockeye, and Silver Salmon breed in local creeks and rivers.

Research and Management Activities

Several natural resource management professors  at Humboldt State University encourage students to work on projects around Humboldt Bay. See the bibliography list below. Humboldt Bay is being considered for a National Estuarine Research Reserve. Humboldt Bay Harbor Recreation and Conservation District is completing a management plan for Humboldt Bay.

SACER (The scientific advisory committee for estuarine research) is a group of local scientists guiding restoration efforts within Humboldt Bay. Over 90% of bay wetlands (6000 acres) were diked and drained from the late 1800’s until the 1960’s. Restoring much of this acreage to productive wetlands will improve the health of the bay and is a goal of many local communities and area residents.

Special Information


Wigi is the the Wiyot Tribe name for Humboldt Bay. The Wiyot have lived off the rich waters and land surrounding Humboldt Bay for several thousand years. The Russian-American Fur Company visited Humboldt Bay in 1806 while trapping sea otters along the coastal waters. A discovery party looking for a shorter route to the gold mines along the Trinity River found Humboldt Bay in December 1849, the first European settlement of the region followed during the next year. The area quickly became a port for shipping agricultural products and lumber all along the Pacific Coast from Chile to British Columbia.


  • Godwit Days bird festival  - mid to late April each year draws visitors from all over the world
  • Audubon leads weekly walks at the Arcata Marsh and Wildlife Sanctuary at the foot of I Street, Arcata 8:30 each Saturday morning all year rain or shine
  • Audubon leads walks at Eureka Marsh, foot of Del Norte Street September through March at 8:30 AM.
  • The Audubon walks at Humboldt Bay NWR are held the 2nd Sunday each month at 9:00 at the Refuge Headquarters at the Hookton Slough exit off Highway 101 ( about 10 minutes south of Eureka).
  • Bird walks are also provided the 1st and 3rd Wednesday each month at 11:00 at the Refuge Headquarters.  Special walks for groups can be arranged by calling (707) 733-5406.

References pertaining to Humboldt Bay

Barnhart, Roger A., M. J. Boyd, and J.E. Pequegnat. 1992. The ecology of Humboldt Bay, California: An estuary profile. U. S. Fish and wildlife Service. Biological Report No. 1. 121 pp.

Base, D.L. 1982. Composition, status, and changes of birds and other wildlife on a tidal marsh restoration site at Humboldt Bay. M.S. Thesis, Humboldt St. Univ. 64 pp.

Carrin, L.F. 1973. Availability of invertebrates as shorebird food of a Humboldt Bay mudflat. M.S. Thesis, Humboldt St. Univ. 84 pp.

Colwell, Mark A. 1994. Shorebirds of Humboldt Bay, California: Abundance estimates and conservation implications. Western Birds. 25: 137-145.

Colwell, Mark A. and S. L. Dodd. 1997. Environmental and habitat correlates of pasture use by nonbreeding shorebirds. Condor. 99:337-344.

Evans, T.J. 1988. Habitat use and behavioral ecology of American Avocets (Recurvirostra americana) wintering at Humboldt Bay, California. M.S. Thesis, Humboldt St. Univ. 128 pp.

Gerstenberg, Ronald H. 1972. A study of shorebirds (Charadrii) in Humboldt Bay, California- 1968-1969. M.S. Thesis, Humboldt State University, Arcata, CA. 207 pp.

Gerstenberg, Ronald H. 1979. Habitat utilization by wintering and migrating shorebirds in Humboldt Bay, California. Studies in Avian Biology. No 2. 33-40.

Harris, Stanley W. 2005. Northwestern California Birds. 3rd edition. Living Gold Press. 460 pp.

Hunter, John E., D. Fix, G. A. Schmidt, and J. C. Power. 2005. Atlas of the breeding birds of Humboldt County, California. Redwood Region Audubon Society, Arcata, CA. 440 pp.

Grosz, R.E. 1992. Ecology of small marshes using three different water sources. M.S. Thesis, Humboldt St. Univ. 121 pp.

Haynes, C.S. 1986. The Arcata Bottoms: Flooding on a changing landscape. M.S. Thesis, Humboldt St. Univ. 123 pp.

Higley, J.M. 1989. Waterbird and raptor use of the Arcata Marsh and Wildlife Sanctuary, Humboldt County, California, 1984-1986. M.S. Thesis, Humboldt St. Univ. 121 pp.

Hoff. C.J. 1979. Bird use of agricultural lands around north Humboldt Bay, California. M.S. Thesis, Humboldt St. Univ. 89 pp.

Hofman, P.S. 1987. Ecological and biological aspects of the Common Snipe in California. M.S. Thesis, Humboldt St. Univ. 88 pp.

Holmberg, N.D. 1975. The ecology of seven species of shorebirds (Charadrii) in north Humboldt Bay, California- 1970-1971. M.S. Thesis, Humboldt St. Univ. 74 pp.

Kelly, John P., J. G. Evens, R. W. stallcup, and D. Wimpfheimer. 1996. Effects of aquaculture on habitat use by wintering shorebirds in Tomales Bay, California. Calif. Dept. of Fish and Game 82:160-174.

Long, Linda L. 1993. The daytime use of agricultural fields by migrating and wintering shorebirds in Humboldt Bay, California. M.S. Thesis, Humboldt St. Univ. 96 pp.

Meretsky, Vicki 1988. Population size and feeding ecology of marbled godwits on north Humboldt Bay, California- July to December 1987. M.S. Thesis, Humboldt St. Univ. 71 pp.

Monroe, Gary W., S. J. Thompson, P. G. Swartzell, B. M. Browning, and J. W. Speth. 1973. The natural resources of Humboldt Bay, California. Calif. Dept. of Fish and Game. Coastal Wetlands Series No 6. 160 pp.

Monroe, Gary W., F. Reynolds, B. M. Browning, and J. W. Speth. 1976. . The natural resources of the Eel River Delta, California. Calif. Dept. of Fish and Game. Coastal Wetlands Series No 9. 108 pp.

Nelson, Eric T.. 1989. The composition, distribution, and seasonal abundance of waterbirds using South Humboldt Bay, July 1987 – June 1988. M. S. Thesis, Humboldt State University, Arcata, CA 77 pp.

Spitler, J. R. 1985. Avian use of newly created wetlands; Arcata, California- April 1980 to April 1981. M.S. Thesis, Humboldt St. Univ. 120 pp.

Ray, Dan. 1982. Present and future management of Humboldt Bay. Pages 77 – 83 In: Christopher Toole and carol Diebel, eds. Proceedings of the Humbolst Bay Symposium. Center for Community Development. Humboldt State Univ., Arcata, CA

Springer, Paul F. 1982. The bird and ammal resources of Humboldt Bay. Pages 60 -67 In: Christopher Toole and carol Diebel, eds. Proceedings of the Humbolst Bay Symposium. Center for Community Development. Humboldt State Univ., Arcata, CA

Stenzel, L.E., J.E. Kjelmyer, G.W. Page, and W.D. Shuford. 1989. Results of the first comprehensive shorebird census of northern and central California coastal wetlands, 8-12 September 1988. Pt Reyes Bird Observ. Rpt. 28 pp.

White, Marshall. 1963. Occurrence, habitat ecology, food habits, and the sex and age relationships of the Wilson Snipe in the Humboldt Bay region. M.S. Thesis, Humboldt St. Univ. 90 pp.

White, Marshall, and S. W. Harris. 1966. Winter occurrence, foods, and habitat use of snipe in northwestern California. J. Wildl. Mgmt. 30 (1): 23-34.

Contact Us

Humboldt Bay National Wildlife Refuge
1020 Ranch Road, Loleta, CA 95551

Chet Ogan
Research Technician-Wildlife
Redwood Sciences Laboratory USFS
1700 Bayview Drive
Arcata, CA 95521
Ph: 707-825-2952

Links to Additional Resources

  • Godwit Days is a local bird fest that features over 100 docent led field trips and activities each April to celebrate Marbled Godwits and other local shorebirds that stage on Humboldt Bay before returning to nesting grounds in Alaska and western Canada.
  • Humboldt BayNational Wildlife Refuge is open year round with trails and docent led walks.
  • California Department of Fish and Game has several wildlife areas around Humboldt Bay and near Crescent City.
  • Redwood Region Audubon Society lists local birding hotspots and checklists for the region. Other specialties that people come to this area for are Varied Thrush, Blue and Ruffed Grouse, and Spotted Owls. The refuges are great places to view Short-eared Owls, White-tailed Kites, Bald Eagles, Peregrine Falcons, and other wintering raptors.
  • Arcata Marsh and Wildlife Sanctuary
  • Humboldt County Convention and Visitors Bureau lists additional areas of interest, local events, and places to stay in the Victorian Seaport of Eureka and surrounding Humboldt County.