Tijuana River Estuary, largest coastal wetland in Southern California, offers intriguing hikes around a marsh and along the beach, and excellent bird-watching.

At first glance, the Tijuana River Estuary (officially the Tijuana River National Estuarine Research Reserve) can appear lifeless. But a closer look, or a look through binoculars, might reveal a marsh hawk, brown pelican, California gull, black-necked stilt, snowy egret, Western sandpiper and American kestrel—just to name a few of the more common birds.

Take a hike and try to keep count of all the birds you see at Tijuana River Estuary. (courtesy, Osborn B, wikimedia)
Take a hike and try to keep count of all the birds you see at Tijuana River Estuary. (courtesy, Osborn B, wikimedia)

Tijuana River Estuary, located about 1.5 miles north of the international border between the U.S. and Mexico, and 15 miles south of San Diego, is an essential breeding ground and feeding and nesting spot for some 370 (!) species of native and migratory birds. Of these species, about 320 are migratory and 50 are residents.

The reserve offers four miles of hiking trails, which lead to excellent bird-watching areas and to the mouth of the Tijuana River, where it meets the Pacific Ocean. Hike around on your own for a mile or two or three, or join a docent-led nature/bird walk.

The reserve is administered by several governmental agencies. The U.S. Fish and Wildlife Service is responsible for managing the Tijuana Slough National Wildlife Refuge, and other natural resources. California State Parks operates the Visitor Center (as well as adjacent Border Field State Park) and offers interpretive programs.

(The greatest threat to the estuary has been, and is, sewage discharges from Tijuana. Sewage from the fast-growing city sometimes contaminates the Tijuana River, which in turn empties into the estuary. Border Field State Park and Tijuana River Estuary have been closed to public use many times as a result of such sewage spills. While sewage contamination continues to be a challenge, improved international relations and the development of the South Bay International Wastewater Treatment Plant have led to major reductions of contaminated flows.)

The Trailmaster is pleased to report that the long-neglected estuary is benefiting from substantial restoration efforts, educational programs and improved access and trails. It’s a vital coastal resource: Tijuana River Estuary is one of the few salt marshes remaining in Southern California, where more than 90 percent of wetland habitat has been lost to development. It’s crucial bird habitat and a key stopover point on the Pacific Flyway.

The visitor center (open Wednesday through Sunday
10:00 a.m. to 5:00 p.m.) has a number of family-friendly exhibits that interpret marshland ecology. My favorite display is the painted floor map of the Tijuana River Watershed on the sidewalk and inside the building. A visitor can “walk” from Mexico across the border, along the waterways of the estuary, and out to the Pacific Ocean. The Clapper Rail Nest Gift Shop offers books and nature-themed gifts.

Docents lead guided nature/bird walks or you can hike a mile or two or three on your own. From the visitor center, pathways lead into the estuary and continue to the Tijuana River mouth. Trails are open daily during daylight hours, dawn to dusk. Be sure to pick up a Tijuana River Estuary Trail Map and the pamphlet “Birds of Southern California’s Coastal Bays and Estuaries before you hit the trail. Binoculars are loaned free of charge.

North McCoy Trail (0.3 mile) offers the opportunity to view many the many birds of the estuary, including the iconic light-footed clapper rail. Two more trails, from trailheads at Fifth Street and Iris, and at Fifth and Grove, lead into the estuary as well.

Though the estuary is almost flat, it’s not completely flat, and very small changes in elevation bring changes in vegetation. At higher elevations are hillocks of coastal scrub, and at the very lowest elevations are mud flats. Between is a marshland of pickleweed and cordgrass.

For an interesting return route or addition to your marsh hike, take a walk along wide, sandy Imperial Beach.

Directions: From Interstate 5 in Imperial Beach, exit on Coronado Avenue (this is NOT the Coronado Bridge exit!). Head west on the avenue (which continues as Imperial Beach Blvd.) 3 miles to a four-way stop. Turn left onto 3rd Street and you’ll spot the Visitor Center (619-575-3613) on the right. (Imperial Beach, CA Latitude/Longitude: 32.5839 / -117.1122