Wildlife & Habitat

California Quail

A mix of several distinct habitat types—open water, riparian, and shrub-steppe upland—along with the lack of other local wetland habitats, elevates the importance of this refuge as a home to a variety of wildlife and plant species.

Aquatic habitats and open water serve as resting and feeding grounds for wintering waterfowl, wading birds and migrating shorebirds. During peak winter migration, the refuge supports large numbers of waterfowl. Mallards and Canada geese comprise the majority of waterfowl, while the American wigeon, green-winged teal and northern pintail account for smaller numbers.

Thick stands of willow and cottonwood represent the riparian zone—the areas on the refuge where land meets water—and is especially important to wildlife because it offers a variety of food and shelter. Osprey nest in the cottonwoods, and bald eagles frequent the area in fall and winter. The thick underbrush provides excellent habitat for many species of songbirds, like yellow warblers and song sparrows, and is also a good place for deer and small animals to feed and rest. During the late summer drawdown, migrating shorebirds can be seen probing the exposed mudflats in search of high energy foods. Colonial nesting birds, like great blue herons and egrets, can also be seen in statuesque stillness, ready to lunge at unwary prey.

The surrounding upland shrub-steppe community comprises the remaining refuge habitat and consists of native sagebrush, bitterbrush and blue-bunch wheatgrass. A variety of wildlife species can be seen using the uplands throughout the year. Unwary visitors may flush ring-necked pheasant or quail while walking through the grass. Mule deer can often be seen browsing on the hillsides at dawn or duck. The melodious song of the western meadowlark drifts over the uplands in spring, while red-tailed and Swainson’s hawks catch summer thermals and soar in search of prey.

The shrub-steppe, representative of plant communities once very common in this part of the country, is threatened by exotic invasive weeds such as cheatgrass, Scotch thistle, star thistle and Russian olive. The native plants cannot compete for water and nutrients as well as these exotics, which thrive in stressed or disturbed conditions. Wildlife, having been sustained for ages by the native plants, start to decline because exotic plants typically do not provide the needed food nor shelter.