The reserve is home to an abundance of various animals. From the birds that soar above to the fish that swim below, you will discover a wealth of biodiversity at the Bolsa Chica Wetlands.


Several species of mammals can be seen at Bolsa Chica. Rabbits and gophers are seen most often in the morning, while ground squirrels are seen virtually all day. Coyotes can sometimes be spotted in the grasses on the Mesa (looking east of the Mesa Trail), and are very important in controlling the rodent population in the area.


If you look carefully, you may be able to spot some reptiles while at Bolsa Chica. Because their bodies cannot produce their own heat, reptiles rely on the heat of the sun and the ground to warm their bodies. We call this cold-blooded or exothermic. Lizards can be seen on the ground or along the wooden fences, basking in the sunlight. Snakes are seen less often, but are occasionally spotted from the trails. Although feared by many, snakes play an important role within their habitat by controlling rodent populations. Rattlesnakes are also present at Bolsa Chica. For more information on rattlesnakes and rattlesnake safety click here.

Marine Vertebrates

Wetlands serve as a nursery for many fish and shark species. About 80 species of fish inhabit Southern California bays and estuaries.

Marine Invertebrates

Invertebrates are animals without backbones. Instead of bones, they have exoskeletons or are soft-bodied. Marine invertebrates lie near the bottom of the food chain in Bolsa Bay, but are above algae, plants, protozoa and plankton. The tens of thousands of birds that come to the wetlands depend upon these animals for their food. Fish that breed and spawn in the wetlands also consume many of these animals.

The invertebrates that live in the wetlands include copepods, amphipods, mussels, clams, horn snails, worms, crabs and many more!


Birds are one of the most abundant and interesting animals to encounter at the reserve. A variety of these feathered creatures can fly, swim, and make a fantastic spectacle. If you’re a birder, or looking to start, visit our page on birds linked below or see a birding checklist here.

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