Wildlife & Habitat
Aleutian Cackling Geese
The San Joaquin River National Wildlife Refuge has played a major role in the recovery of Aleutian cackling geese by serving as an important wintering area and continues to be of major importance to this species. By the mid-1970s, the total population of Aleutian cackling geese was fewer than 1,000. Removing nest predators from the breeding grounds in Alaska’s Aleutian Islands and improving wintering habitat in the Central Valley resulted in the goose being delisted as an endangered species and a population well over 100,000 and growing. Restoring wetlands and providing grasslands and croplands at this refuge has provided ideal wintering habitat for the geese.
Riparian habitat refers to the communities of plants along a river or stream. It is estimated that ninety-five percent of the San Joaquin Valley’s riparian woodlands were lost during the last century due to changing land uses. This critical habitat is being restored at the Refuge. Within the borders of the San Joaquin NWR is one of California’s largest riparian forest restoration projects: over ½ million native trees and shrubs such as willows, cottonwoods, oaks, blackberry, and rose have been planted across 2,200 acres of river floodplain creating the largest block of contiguous riparian woodland in the San Joaquin Valley. This important riparian woodland habitat is host to many rare animals.
Swainson’s hawks nest in the canopy of tall cottonwood trees. Herons and cormorants form communal nesting colonies within the tops of the large valley oaks. Endangered riparian brush rabbits have been re-introduced to this restored habitat from captive-reared populations. These woodlands also support a diversity of breeding songbirds including grosbeaks, orioles, flycatchers, and warblers, as well as the least Bell’s vireo – an endangered species which had last nested in the San Joaquin Valley more than five decades ago.
Riparian Brush Rabbits
The Refuge is working toward another successful endangered species recovery. Through efforts at the Refuge, there is hope that the highly endangered riparian brush rabbit will join the Aleutian cackling goose as a fully recovered species. Riparian brush rabbits are endemic to the riparian woodlands of California’s Central Valley. By the 1990s, their numbers dwindled near extinction due to habitat loss and degradation. The last known population was found along the Stanislaus River in San Joaquin County. Through a partnership with the Endangered Species Recovery Program at California State University, Stanislaus, captive-bred rabbits have been released into the Refuge’s well-suited dense riparian woodlands. By establishing a new large population of rabbits, these efforts will help foster successful recovery for this endangered mammal. The Refuge contains the largest wild population of riparian brush rabbits in the world.