Coming to Terms with Terns
Related to seagulls, terns are classified under the bird family, Laridae, and although similar in appearance to gulls, they have constantly intrigued me because of the beauty of their flight. They are usually identified by their black and white plumage, their long, angular wings and tail feathers displayed in flight, and their behavior of diving vertically into the water from 20 to 50 feet (6 to 15 meters) to catch fish. Gulls do not dive. Additionally, terns have a straight, sharply-pointed bill, whereas gulls possess a more hooked one. However, some gulls (such as the laughing gull) possess dark-colored heads similar to terns, making recognition more difficult, especially outside the breeding season when gulls and terns lose this feature.
I spotted my first tern as a teenager back in October 1963 at Spurn Point, England, and was told to record it as a “commic” tern. It was flying far out at sea, and I later discovered that this was a “portmanteau” word for recording that we had just seen either a common tern or arctic tern, but that the bird was too far away to distinguish which variety. Arctic terns have shorter legs and a deeper red beak, and the common tern also has a black tip at the end of a more orangey beak.
Later, during my formative birdwatching years, I also managed to record Sandwich, black, and little terns. The UK hosts five species of these birds for breeding (common, roseate, Arctic, Sandwich, and little terns), another five that regularly visit during migration, and a further six that are rare visitors.
Worldwide, there are close to 40 species of these slender, graceful, water birds that are usually black and white, and in most cases, more white than black. To the casual beachgoer they may look alike. They display long, pointed wings, long tail feathers, and typically inhabit sea coasts and inland waters. These birds fly over water as swallows do over land, and with quick, agile maneuvering, they dart through the air and plunge-dive into the water, capturing their prey by piercing them with their pointed bill. They may also skim the surface of the water for the purposes of drinking. The best way to distinguish between species of tern is to record their size, the color of their bill (red, orange, yellow, or black), the existence or otherwise of blackish wing tips, and the length of their tail streamers. Also, elegant, Royal and Sandwich terns display a ragged crest at the back of their heads especially during breeding season.
Additionally, terns are known for the great distances they travel annually, especially the Arctic tern that breeds in the summer Arctic and migrates south for winter in Antarctica. These birds can travel around 25,000 miles (40,000 km) each year, gliding as well as flying, usually out at sea, and taking around 40 days for the one-way migration.
Arctic tern migration map
There are at least 17 types of native and migratory tern species recorded in North America. During my years living in Northern California, I have watched the fishing antics of the common tern, the Forster’s tern, the Caspian tern, and the elegant tern. Some varieties breed locally and others, like the common tern, are visitors during migration. The one California tern I have not so far seen is the least tern, the smallest of all tern species, about the size of a large songbird. They breed in small numbers in the San Francisco Bay Area, but because they are an endangered species, they are subject to intensive management and protection from humans who risk inadvertently trampling on their nests. It is believed that they migrate to parts of Central and South America for winter.
The California least tern has a distinct white patch on its forehead, interrupting its otherwise solid black cap, and in summer has a yellow bill with a black tip, and yellow feet. It usually flies low over the water with quick deep wingbeats, using its very pointed, sharp wings, and with a hunched-over look, with shrill cries of “kellick” or “kip-kip-kip” usually heard just before being seen plunging into the water to catch its tiny prey – typically small fish. It has a forked tail and black wing tips. The species nests in colonies, usually around 25 pair per colony, scratches out a “scrape” in the sand or gravel, and lays three green eggs blotched with brown.
Next and eggs of least tern
So you can imagine my excitement when, at the start of August 2021, I found myself on vacation in San Diego County, and discovered that least terns were nesting a few miles away, close to the Mexican border, at the Tijuana Estuary, and under the protection of the Tijuana Slough National Wildlife Reserve. It was a dull, cool, Friday morning as I and my friend made our way south for about 30 minutes, to arrive at Imperial Beach where we quickly located the Reserve’s Headquarters. We were greeted warmly and offered abundant advice. Immediately, I was told that Bewick’s wrens, scrub jays, dark-eyed juncos, bushtits, song sparrows and Anna’s hummingbirds had been seen close to the building that morning. These were all species that commonly visit my backyard and I felt a little disappointed if this was all I was going to see. However, with the help of a trail map, we were soon on our way across the marsh, to the accompaniment of the sound of helicopters from the nearby helicopter base. In the distance was Tijuana, and the US – Mexico border wall, undulating along the hills and eventually running down to the beach and into the Pacific Ocean.
Tijuana Wildlife Reserve
Almost immediately, we encountered juvenile black-crowned night herons waiting to catch fish, and black phoebes fluttering in search of insects, but despite close scrutiny of the nearby marsh, we failed to see or hear the very rare, hen-sized, Ridgway’s light-footed rail, found only from Santa Barbara County, CA, south along the coast into northern Mexico. It is a sub-species of the Ridgeway’s rail that was so named in 2014 (replacing the California Clapper rail), to distinguish this species of bird from the Clapper rails that inhabit the Atlantic and Gulf coastlines of North America and throughout the Caribbean.
Other bird species we did record included the American kestrel, northern harrier, marbled godwit, cliff swallows, northern mockingbird and a Forster’s tern fishing in the tidal lagoon, but no sighting of a least tern.
The warden commiserated with us back in headquarters, and told us to visit the beach to the south of the town. After treating ourselves to ice cream on the local pier, we walked south along the beach towards Tijuana. At first we encountered several groups of large, stocky shorebirds, called willets, searching for food at the water’s edge, and could see several terns fishing out at sea. I believe they were elegant terns, and maybe one large Caspian tern.
But just as we were about to end our search and return to our vehicle, we heard overhead the cry of “kip-kip-kip”, as two least terns passed by. They are closely related to the Old World little tern, but are considered a separate species, largely based on voice difference. A beautiful sight and I had achieved my ambition. Nothing more mattered. It was time to return home. My friend probably thought me mad or crazy because of all my excitement, but there is something fulfilling in spotting a rare bird for the first time, and adding it to your life list. I wish the same for the readers of this Blog. Birding is a fun hobby, and there is always something different to see and something new to learn.