Van Rossem's Gull-billed Tern

Now that I am no longer a servant of Least Terns (whose eggs and chicks are prey for Gull-billed Terns), I can now come out publicly and say that I'm a big proponent of Gull-billed Terns.

For many years I only saw them infrequently...it wasn't until taking a job near California's Salton Sea in 2007 that I saw them on the regular. They stood out in stark contrast to their bizarre, often disgusting surroundings; this incongruity made me pay special attention to them.


Aside from skimmers, Gull-billeds are pretty unique for a tern...you can find them hunting for insects, amphibians, reptiles, crustaceans, fish, bird eggs and young...they are truly opportunistic.

Gull-billed Terns are cosmopolitan, and found on multiple continents. In California, the local subspecies is Van Rossem's Gull-billed Tern, whose global population is thought to be around only 800 pairs. Despite this worrisome number, the U.S. Fish and Wildlife Service recently declined to add them to the Endangered Species List.

The good news is that while the Salton Sea population has been more or less stable over the last couple of decades, the San Diego population is slowly increasing.



What a slick-looking bird. Economy of style in full effect.

Along the shores of Imperial Beach, Gull-billed Terns specialize on grabbing mole crabs (aka "sand crabs") from a few inches of water, when the tide is right. When the tide isn't conducive to mole-crabbing, Gull-billeds may instead focus on terrestrial prey like lizards and bird chicks and eggs.

While normally devoured on the wing, they will occasionally land to take the time to properly demolish and choke down big ones.

Here's a juvenile. Note the marked "flag" dangling from its ankle. This population, which nests in the Salt Works of South San Diego Bay, hosts a number of birds with metal bands, field-readable flags, and even radio transmitters.

All of the photos here were taken between the mouth of the Tijuana River and Imperial Beach, CA.

Pic Of The Week

Light-footed Clapper Rail vs. American Avocet. The avocet won handily. No wonder rails spend so much time lurking in the grass, they are easily vanquished. Tijuana Slough National Wildlife Refuge, CA.

I think I'll start posting a weekly photo every Saturday or Sunday, for your viewing pleasure. Who wants to spend their weekend reading a full-blown blog?

Hexed At Tijuana Slough

American Pipit in breeding colors. It was roaming the beach, chasing flies relentlessly around the mounds of kelp and algae.

One of the few places I've birded around here in the past was the mouth of the Tijuana River, when the Belcher's Gull showed up back in the 90's. There aren't any megacripplers like that hanging out there now (and yes, I saw the hell out of that bird), but I do remember it as looking like an amazing place to stare at the birdlife....so not long I ago I found myself retracing the steps of a younger, even nerdier version of Seagull Steve.

The place looks about the same as I remember it. Tijuana Slough National Wildlife Refuge (aka Tijuana River National Estuarine Research Reserve) has lots of tidal channels and saltmarsh, with a very birdy river mouth accessed from TSNWR trails, Border Field State Park or Imperial Beach. Nesting Yellow-crowned Night-Herons nearby are a nice perk as well. Offshore you can see the Coronado Islands, which lie in Mexican waters. They hold Brown Boobies and American Oystercatchers, birds I hold in high regard.

Unfortunately, on the day of my visit it was exceedingly dark and gray, which just makes me want to back there even more. It will happen soon. All photos today are from TSNWR.

Snowy Plover. This, at the moment, is the bird my life revolves around...that is, until the Least Terns start nesting as well.

One of the perks of the San Diego area is its abundance of terns. As you may know, I am a huge proponent of birds with forked tails. Forster's Terns are one of a number of tern species that breed in San Diego County.

Gull-billed Terns abound here, which is not something I remember from years ago. I'm not certain how their population over at the Salton Sea is doing, but they have been increasing in San Diego County. The Californian/West Mexican subspecies, Van Rossem's Gull-billed Tern, was recently petitioned to be listed under the Endangered Species Act, but Fish & Wildlife declined to do it (probably more for ill than good).

Do you see? It's like the Mercedes of terns.

This was the first time I managed to get some deec Long-billed Curlew pictures...the terns and shorebirds along the beach are somewhat acclimated to people, which is what a bird has to do to get by in these parts.

You see this clump of mussels? Whimbrel heaven. Delicious.

While California may be devoid of frigatebirds, at least we have Brown Pelicans to fill our skies.

This was the rarest sighting of the day. It's a birding church group. I have no idea what the priest is doing in this picture, maybe trying to part the slough? Put a hex on me? At any rate, it's a good thing to see.

Savannah Sparrow. When I took this picture I thought it was a Belding's (the locally common but endangered subspecies), but now I don't think it is, it's not dark enough. How embarrassing!

I never get tired of watching Sanderlings' neverending struggle to be as close to the water as possible without actually touching it. The Black-bellied Plover left for drier pastures.

There aren't many crappier looking birds than worn, first-year Western Gulls. They truly look trashy. So trashy, in fact, when they pick up an unappealing clump of mussels (maybe it was the Whimbrel's?), it makes them look better.