California Least Tern

California Least Tern (Sternula antillarum browni)

You may have noticed the terns hovering over our oceans and estuaries and gracefully dipping and diving.  At first glance they look like seagulls, but they’re more streamlined and agile with pointed wings and often with black windswept caps.  The smallest of these terns, the California least tern, is an endangered species that nests on the sand at the end of the spit near the estuary.

This species has a very limited breeding range, including Southern California, a few areas in San Francisco Bay, and northern Baja California. Because the terns lay their eggs in small depressions in the sand, they prefer unfrequented sandy beaches close to estuaries and coastal embayments for their nesting sites. By the 1960s suitable nesting areas were severely reduced due to coastal development, the introduction of invasive plants and intense human recreational use of beaches. As a result, the tern’s numbers diminished from uncountable thousands to a few hundred by 1970, when the least tern was added to the Federal Endangered Species List.

The beach at the end of the spit is a treasure because it’s one of few beaches within the California least tern’s historic range that remains relatively undisturbed. Beaches closer to developed areas are unsuitable for the species due to recreational uses and dogs that disturb the vulnerable nests.  But even though this nesting colony is some distance from development, it’s still vulnerable to some human recreation, dogs, predators like coyotes, and invasion of nonnative plants such as iceplant and sea rocket that render the habitat unsuitable.

Over the last few weeks, Pro Esteros, with assistance from La Alianza, has been restoring the breeding grounds for the California least tern before they return from their winter homes in South America.  There has been a concerted and successful effort, primarily among Mexicans from Ensenada and Tecate but also from local ExPats, to remove these invasive plants and provide the wide open nesting areas the least terns prefer.  On June 1, a group will gather to install fencing around these restored areas to protect the terns from humans, dogs, and predators.

We are incredibly fortunate to have a stretch of beach so ideal for these rare and endangered birds, allowing us the very special opportunity to see and protect them. Let’s do everything we can to ensure they continue to have a place here for years to come.