Seasons of Wildlife
Each season brings a new look to the refuges with a variety of wildlife. There's always something to see, whether its waterfowl in the winter, shorebirds in the spring/fall, or breeding neotropical migrants in the summer.
Seasons of Wildlife <-- Click here to learn more about what wildlife you might see during the year.
Along with the millions of waterfowl, shorebirds, raptors, waterbirds and migrant songbirds that can be found using the refuges of the Sacramento NWR Complex, there is also a small variety of mammals including opossums, raccoons, coyotes, skunks, jack rabbits, river otters, beavers, muskrats, and more that live on the refuge.
Wildlife Checklist <-- Click here to see the Complex's Wildlife Checklist.
What wildlife have visitors and staff been seeing on the Complex? We encourage visitors to report to us any sightings of rare, unusual, or unique animals on our refuges and the surrounding areas. Check out the most recent sightings on eBird.
Refuge biologists conduct monthly waterfowl surveys.
Waterfowl Surveys <-- Click here to see the Complex's Waterfowl Surveys
How are surveys conducted?
Wildlife surveys are conducted once a month, mid-month, on all wetland refuges of the Sacramento NWR Complex. All waterfowl, shorebirds, waterbirds, gamebirds, raptors, and a handful of mammals and other songbirds are tallied on every single unit (pond/field), using a standardized survey route, a window-mounted spotting scope and binoculars. Using the same observer for each refuge helps maintain consistency (some of the biologists have maintained their routes for over 20 years), assuring a strong index over time.
Routes are designed to take advantage of vegetation barriers, viewing lanes, and flight patterns to maximize viewing, reduce disturbance, and increase the likelihood that flushed birds will fly to an area that the observer has already counted. The observer approaches each pond and takes an initial count. When numbers per pond are low (in the hundreds), a count of each species is done separately. When numbers per pond are in the thousands, all species except for ducks are counted separately, and then ducks are counted as one group and a species composition is applied to that group (ie 1% mallard, 4% gadwall, 10% shoveler, 20% wigeon, 25% green-wing, 40% pintail). Composition can change even within a pond, as some species such as teal will concentrate in certain areas, so multiple groups may be counted and described with different compositions across a single pond.
Depending on flock size, birds may be counted as singles, or in groups of 5, 10, 20, 50, 100, or even 1000 (the only option when a group of 20,000 birds take flight). The smaller the grouping that the observer uses for counting, the higher the accuracy.
Each pond/field is scanned from multiple viewing points, with the goal of seeing and counting all visible wildlife. Auditory cues can also be used, especially for secretive marsh birds such as rails or bitterns.
Following a survey week, biologists transcribe their data and enter it into a database. This data is then used to analyze bird use of each pond/field, and can be tied to management data to assess the effectiveness of past treatments, or identify the need for future efforts. It helps managers identify units that are critical for supporting wintering waterfowl, breeding birds, or special status species, which in turn guides decisions when facing drought, water restrictions,
or other threats. When rolled up to the refuge level, population trends and distributions over time can be assessed. The data is also pulled to feed into larger survey efforts for a variety of species groups at a statewide level.
Wildlife Depredation Issues?
If you are experiencing problems with wildlife depredation on your private property, you can find information about what you can do by visiting USFWS Migratory Bird website.
Mountain lions are residents along the Sacramento River, and there are occasionally sightings on Sacramento River NWR, and rarely on the other refuges of Sacramento NWR Complex. Click here to learn more.
Endangered and Threatened Species
The Sacramento National Wildlife Refuge Complex is home to a number of Federal and State threatened and endangered species. Click here to see a List of Threatened and Endangered Species that occur here.