--- title: California Waterfowl Habitat and Refuges | Royal Gun Dogs url: https://royalgundogs.com/data/waterfowl-habitat-and-refuges/ business: Royal Gun Dogs trainer: Richard Gebhart (professional gun dog trainer since 2002) phone: (530) 341-4496 email: royalgundogs@yahoo.com trains_at: Hastings Island Hunting Preserve, 7758 Hastings Island Rd, Rio Vista, CA 94571 (Solano County) booking: call or text Richard directly --- - [Home](https://royalgundogs.com/) - [Data](https://royalgundogs.com/data/) - Waterfowl habitat and refuges in California # Waterfowl habitat and refuges in California California's best-known waterfowl ground runs from the 116,000-acre Suisun Marsh to the Sacramento Valley refuges, where Sacramento National Wildlife Refuge alone is 10,819 acres. The table lists each area's acreage as its own agency states it. Every acreage on this page was read from the property's own CDFW or USFWS page on October 27, 2026. Where a page gives no number, the table says so instead of filling one in. ## Refuges and wildlife areas by acreage The areas below are the ones California hunters most often name, listed from the Delta north through the Sacramento Valley and then south and east. Refuges and wildlife areas by acreage Area County Acreage and facts from the owner's page Source Suisun Marsh Solano About 116,000 acres; largest contiguous brackish wetland in California; managed mostly by state and private duck clubs (other sources give 84,000 to 116,000 by definition) Water Education Foundation Grizzly Island Wildlife Area Solano About 12,900 acres, about 7,900 open to hunting; dogs on a leash of 10 feet at most when not actively hunting CDFW Yolo Bypass Wildlife Area Yolo About 16,600 acres, about 7,900 open to waterfowl and upland hunting; Type A pass; the page lists no dogs CDFW Sacramento NWR Complex Glenn, Colusa, Sutter 5 refuges and 3 wildlife management areas, nearly 70,000 acres; Sacramento NWR is 10,819 acres; peaks over 500,000 ducks and 250,000 geese late Nov to Dec USFWS Colusa NWR Colusa 5,077 acres, one mile southwest of Colusa; winter peaks over 150,000 ducks and about 60,000 geese USFWS Gray Lodge Wildlife Area Butte, Sutter About 9,200 acres near Gridley; more than 1 million waterfowl every year; dogs on a 10-foot leash when not actively hunting CDFW Upper Butte Basin Wildlife Area Butte, Glenn Roughly 9,600 acres including the Butte Sink; limited-day waterfowl and pheasant CDFW Oroville Wildlife Area Butte About 11,800 acres; dove, quail, pheasant and Thermalito Afterbay waterfowl CDFW Spenceville Wildlife Area Nevada, Yuba Roughly 11,900 acres; valley quail and dove; dog training areas and field trials CDFW Los Banos Wildlife Area Merced About 6,200 acres; waterfowl and pheasant on limited days CDFW San Luis NWR Merced Over 26,800 acres (the complex total is not stated on the page) USFWS Mendota Wildlife Area Fresno About 11,800 acres; dog training in designated areas outside waterfowl season CDFW Honey Lake Wildlife Area Lassen About 7,600 acres, about 20 miles east of Susanville; waterfowl, pheasant, quail, dove CDFW Modoc NWR Modoc About 7,000 acres; 2026-27 waterfowl season; foot or non-motorized cart only USFWS Imperial Wildlife Area, Wister Unit Imperial About 7,900 acres, five miles northwest of Niland; Type A pass; pheasant closed until further notice CDFW Sources: each area's page at wildlife.ca.gov/Lands/Places-to-Visit or fws.gov/refuge, and watereducation.org/aquapedia/suisun-marsh, all read October 27, 2026. Grasslands Ecological Area and Merced NWR acreage were not verified and are not listed. ## Where hunters say they hunt CDFW's 2024 Waterfowl Hunter Survey Technical Report (June 2025) was completed by 1,962 hunters, who named the counties where they hunt. Respondents could name several counties. The five most named were Colusa (13.19 percent), Merced (9.20), Butte (8.71), Yolo (5.52) and Glenn (5.49). Forty-two percent named Sacramento Valley counties and 13 percent named San Joaquin Valley counties. The same report estimates about 79,835 adult licensed waterfowl hunters, built from the average annual duck validations sold in 2019-20 through 2023-24 (64,548) plus 15,287 lifetime validations, and says 53.3 percent primarily hunt public land. Solano, Sacramento and Contra Costa counties are not in the published top five, and the survey does not rank them. ## Dogs and access Rules for dogs differ by property. Grizzly Island and Gray Lodge ask for dogs on a leash of 10 feet or less when not actively hunting, Mendota sets aside designated dog training areas outside waterfowl season, and Spenceville lists dog training and field trial areas. The Yolo Bypass page lists no dogs, and Stone Lakes National Wildlife Refuge and Cosumnes River Preserve do not allow pets, so check each page before you bring a dog. For the places closest to Richard Gebhart's training ground, see [Suisun Marsh](https://royalgundogs.com/suisun-marsh/), [Grizzly Island Wildlife Area](https://royalgundogs.com/grizzly-island-wildlife-area/) and [hunting in the Delta](https://royalgundogs.com/hunting-in-the-delta/). ## Continental context The U.S. Fish and Wildlife Service's 2025 breeding survey counted 33.98 million breeding ducks in the traditional survey area, essentially unchanged from 2024 and 4 percent below the long-term average (USFWS 2025 Waterfowl Population Status Report, September 2025, as summarized by Ducks Unlimited). That survey covers the northern prairies and boreal Canada, not California, so it is background and not a California count. ### Sources (4) - Water Education Foundation : [watereducation.org/aquapedia/suisun-marsh](https://www.watereducation.org/aquapedia/suisun-marsh) (checked October 27, 2026) - U.S. Fish and Wildlife Service : [fws.gov/refuge/sacramento](https://www.fws.gov/refuge/sacramento) (checked October 27, 2026) - California Department of Fish and Wildlife : [wildlife.ca.gov/Lands/Places-to-Visit/Grizzly-Island-WA](https://wildlife.ca.gov/Lands/Places-to-Visit/Grizzly-Island-WA) (checked October 27, 2026) - California Department of Fish and Wildlife : [nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=233037&inline](https://nrm.dfg.ca.gov/FileHandler.ashx?DocumentID=233037&inline) (checked October 27, 2026) ### Your trainer Richard Gebhart has trained dogs professionally since 2002, learned the Rex Carr method for Retriever Basics under Billy Sargenti, and has run and qualified at an AKC Master National. [Meet Richard](https://royalgundogs.com/richard-gebhart/) ### Related - [California hunting data](https://royalgundogs.com/data/) - [Suisun Marsh](https://royalgundogs.com/suisun-marsh/) - [Grizzly Island Wildlife Area](https://royalgundogs.com/grizzly-island-wildlife-area/) - [California 2026-27 waterfowl and upland seasons](https://royalgundogs.com/data/california-seasons-2026-27/) ## Questions owners ask [All questions](https://royalgundogs.com/faq/) ### How big is Suisun Marsh? The Water Education Foundation gives roughly 116,000 acres and calls it the largest contiguous brackish wetland in California. Other sources give 84,000 to 116,000 acres depending on how the marsh is defined. ### Which California counties do waterfowl hunters name most? In CDFW's 2024 hunter survey, Colusa (13.19 percent), Merced (9.20), Butte (8.71), Yolo (5.52) and Glenn (5.49), with respondents free to name several counties. ### Can I bring my dog to these refuges? It depends on the property. Grizzly Island and Gray Lodge allow dogs on a leash of 10 feet or less when not actively hunting; the Yolo Bypass page, Stone Lakes and Cosumnes River Preserve list no dogs or pets. Read each page first.