As winter settles across the Pacific Flyway, managers at the Sutter National Wildlife Refuge track a seasonal surge, welcoming peak waterfowl counts that average 1,800,000 birds by the end of November U.S. Fish & Wildlife Service. Operating alongside several other protected zones in Northern California, the refuge balances heavy migratory traffic with active habitat maintenance and limited public access Sacramento National Wildlife Refuge Complex.
The site serves as a vital corridor within the larger Sacramento National Wildlife Refuge Complex, which encompasses five national wildlife refuges and three wildlife management areas. While visitors frequently seek out locations for auto tours, bicycling, and photography across the broader complex, Sutter National Wildlife Refuge itself maintains a more restricted footprint, offering limited seasonal trails and regulated hunting opportunities.
Seasonal Shifts and Wildlife Populations
The landscape undergoes transformations throughout the calendar year, directly impacting local wildlife viewing conditions. January kicks off the year with 100% of the wetlands flooded and waterfowl counts averaging 995,000, though viewing can prove less reliable as birds disperse to find food.
Partnerships powering reliable water for agricultural communities and healthier ecosystems.Last week, the Bureau of Reclamation joined @DucksUnlimited, @USFWS, state agencies, water districts, and local partners to celebrate the upgraded pump and lift station at Sutter… pic.twitter.com/Vld3Z63tA4
By February, winter burning operations begin to rejuvenate vegetation and nutrients, supporting an average of 548,000 waterfowl across 99% flooded wetlands. As spring approaches in March, water drawdowns start to germinate food plants and prepare the grounds for summer field work. Waterfowl numbers decline during this northward migration, averaging 243,000 with 95% of the wetlands remaining flooded.
April brings stopping shorebirds and neotropical songbirds making use of shallow drawdowns, dropping waterfowl averages to 80,000 across 75% flooded wetlands. Summer residents arrive for nesting in May, bringing waterfowl counts down to an average of 6,700 with only 15% of the wetlands flooded.
During June and July, staff conduct irrigations to bring food plants to maturity, run grazing programs to manage invasive species while encouraging native plants, and execute ongoing habitat maintenance. Waterfowl numbers remain during these summer months, averaging roughly 6,900 in June, 6,300 in July, and 23,000 in August, when summer residents like mallards, wood ducks, herons, egrets, grebes, swallows, turtles, snakes, jackrabbits, deer, and otters remain active.
Fall flood-ups begin in September, staggered to supply fresh nutrition for newly arriving migrants alongside southward-moving shorebirds, raising counts to an average of 348,000 with 25% of wetlands flooded. The influx arrives in October as ducks appear by the thousands, pushing counts to 1,500,000 and 75% wetland flooding.
November marks the peak of the season as geese arrive by the thousands, driving total waterfowl averages to 1,800,000 across 95% flooded wetlands, accompanied by evening fly-offs at dusk as birds forage in the rice. December maintains high activity, with waterfowl counts averaging 1,400,000 and 100% of the wetlands flooded while raptor numbers peak as they follow the waterfowl before ducks disperse across the valley at the end of the month, as goose numbers peak.
Administrative Details and Public Guidelines
The headquarters for the Sacramento NWR Complex is located at the Sacramento National Wildlife Refuge, situated at 752 County Road 99W in Willows, CA 95988. Administrative offices operate Monday-Friday, 8 a.m. – 4 p.m., though they remain closed on all Federal Holidays. Inquiries can be directed to the office via phone at (530) 934-2801 or through email at [email protected].
The refuge does not rescue, rehabilitate or accept animals. Members of the public encountering distressed wildlife are instructed not to call the refuge regarding injured or orphaned animals, but instead to consult external resources such as the California Department of Fish and Wildlife’s Native Wildlife Rehabilitation.
