Located about two hours south of Sacramento, the Merced National Wildlife Refuge is an expansive habitat encompassing more than 10,200 acres of vernal pools, riparian areas, native grasslands, and wetlands in California. It was established back in 1951 to serve as a habitat for wintering waterfowl, which were damaging crops in the adjacent farmlands. Over the past decades, improvements in agricultural techniques and refuge management have helped reduce crop and wildlife issues.
The Merced National Wildlife Refuge is home to the Pacific Flyway’s largest wintering population of species such as Ross’s geese and lesser sandhill cranes. During the autumn season, over 60,000 arctic nesting geese and 20,000 cranes take a six month break from their annual migrations from Canada and Alaska to seek shelter in the refuge. Here, they join other migrating aviary species such as shorebirds, waterbirds, and waterfowl, making the refuge an incredible winter phenomenon each year.
A Breeding Sanctuary
Merced National Wildlife Refuge also serves as an important breeding habitat for species such as marsh wrens, cinnamon teal, Swainson’s hawks, mallards, burrowing owls, gadwall, and tri-colored blackbirds. The tri-colored blackbirds in particular, create colonies of over 25,000 pairs in the refuge.
Other animals including beavers, coyotes, long-tailed weasels, ground squirrels, and desert cottontail rabbits also make the refuge their home year-round.
Vernal Pools Within the Refuge
One of the refuge’s most unique features are its vernal pools. These are special pools that are created when shallow depressions with clay soils are filled with winter rainwater. The pools become populated with fairy and tadpole shrimp, which emerge from cysts buried within the soil during the past year. Tiger salamanders and other amphibians also lay their eggs and rear tadpoles in the refuge’s vernal pools. The incredible variety of aquatic invertebrates populating these vernal pools serve as a source of food for migrating and wintering birds as they get ready for the long journey north towards their breeding grounds.
Wildlife Observation and Other Activities
Visitors at the Merced National Wildlife Refuge can get a glimpse of the refuge’s variety of species in their natural habitat through the auto tour route. The route includes two elevated observation decks equipped with spotting scopes, providing an even closer view of the wildlife. Visitors can also see interpretative panels containing information on the wildlife, habitats, and methods used to preserve and manage the refuge.
The auto tour route is five miles long, and loops around the vast upland grasslands and seasonal wetlands, giving visitors breathtaking views of the thousands of lesser sandhill cranes, Ross’s Geese, and the large concentration of shorebirds and dabbling ducks during the fall and winter.
Another highlight for wildlife viewing is the Meadowlark Trail, which meanders throughout the various habitats located within the refuge, including seasonal wetlands, native grassland meadows, and riparian corridors. The diverse assortment of habitats attracts different bird species each year, which vary depending on the season.