Turning to Terns

NOTE: Identifying terns can be tricky, and for this post I am indebted to Chuck Almdale who graciously shared his knowledge. 

After an absence of several months, and newly returned from their wintering grounds in Central America, the Elegant Terns are back at Zuma Beach. With their distinct tufted crest feathers and yellowy-orange beaks, they are a welcome sight, and stand smaller in stature next to the gull species on the beach.

A Committee of Elegant Terns

Santa Monica Bay Audubon Society (SMBAS)’s Social Media and Blogmaster officer and bird expert Chuck Almdale has been keeping a census on birds seen at the Malibu Lagoon since 1979.  He reports that forty-five years ago, Elegant Terns were seldom seen north of San Diego.  They have since increased in number in Los Angeles County. The Audubon guide advises their range is moving northward in California. They are now seen in season at the Malibu Lagoon and area beaches. Nonbreeding head plumage is white and gray on top, which will morph into black as the birds mature.  

Elegant Terns at Zuma Beach

According to the Santa Monica Bay Audubon Society’s handy identification guide for terns (including superb photographs), bill color changes from pale yellow (juveniles) to orange and even red (as adults). Breeding season intensifies the color of the parents’ beaks.

Their wings are quite long relative to their body size, and this may be why they are so named.  SMBAS indicates the wingspan ranges from 29.9 to 31.9 inches. Length from bill to tail ranges from 15.3 to 16.5 inches.

Offshore in California, sardines are Elegant Terns’ favorite food.  They plunge-dive for them, similar to California brown pelicans.  Terns use their long, thin bills to carry up to several small fish at a time back to mates and nestlings during breeding season.  Generally, they will take small fish found near the surface of water, be it in “marshes, rivers, bays, and oceans.” (E. S. Brinkley and Alec Humann, “The Sibley Guide to Bird Life and Behavior, 1st ed., p. 298).

These terns haven’t always had an easy time of it. On Isla Rasa in the Gulf of California, where it has been determined that almost the entire population of Elegant Terns nests today, eggs and chicks were decimated by black rats and house mice during the late 19th century. Commercial egg harvesting began in the early 20th century.  Fishermen took upwards of half a million eggs per year, selling them for food until that practice was banned and ceased in the 1980’s. Rodents were removed as a predator by 1995.

Sardine fishing and climate change continue to challenge the birds in their wintering grounds in Mexico, and in the Western United States where they summer.  They’re adapting, and now nest in three California locales: San Diego saltworks, Bolsa Chica Ecological Reserve, and Los Angeles Harbor.

Next time you walk the beach, take a moment to peer at a group of sea birds and see if a committee of terns isn’t mixing it up with gulls.

Published by Mashabu

Earnest observer of our natural world.

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