Coastal Migrant Traps

by Mike Stiles

In the Fall, and more specifically mid-September through mid-October, many birds—as well as many birders—can be found in our coastal migrant traps. These are areas of dense trees, often willows, but also pines and Eucalyptus, often associated with creeks or other bodies of water along the immediate coastline. These areas of thick trees harbor many insects for the warblers and vireos and others to refuel as they migrate down our coastline.

The allure of these "traps" is the possibility of finding vagrants, the birds far out of their normal range, especially the warblers and vireos that are common on the east coast. It is unclear why this happens, but many birds will migrate down the "wrong" coast, and we are glad they do. It is very exciting to find a rare bird and the possibility of a "mega-rarity," a first for the county or even the state is a possibility.

The names of California migrant traps are well known to birders everywhere, from Point Reyes in the north to the Tijuana River mouth to the south, but without a doubt, the most remarkable finds come from the Farallon Islands, about 30 miles offshore from the Golden Gate Bridge. This tiny island complex is the ultimate migrant trap . . . nowhere else to go. . . and has contributed many California first records, and can boast of a bird list of over 400 species. It is not open to the public, but a bird banding operation has been in place since 1969, operated by the Point Reyes Bird Observatory.

In our county, birders flock to places like Oso Flaco Lake, Oceano Lagoon, Montana de Oro, Morro Bay, and the numerous creek mouths on the north coast, such as Santa Rosa, San Simeon, and Arroyo de la Cruz. If you bird these areas, listen closely. In the fall, birds will travel in large flocks, containing many species. The constant chatter and the sound of bill snaps as the birds catch insects will direct you to the feeding frenzy. If you are lucky, the flock will be too big for just one pair of eyes.

Oceano Lagoon and Campground is our most well-known and most well-birded migrant trap. The dense willows around the lagoon and the pines in the campground have contributed greatly to our county bird list. Birds like Arctic Warbler (well out of its northern Asian range), Connecticut Warbler, Painted Redstart, Cerulean Warbler, and Yellow-green Vireo, can all make for an exciting migration season.

Montana de Oro State Park has yielded its share of rare birds. The Spooner Cove Campground and willows along Islay creek (especially where it outfalls on the beach), Hazard Canyon, and Coon Creek are all prime birding areas. The only real problem with finding a rare bird in the park, is that there is little cell phone reception to alert the others of your find.

Oso Flaco Lake has great potential, but I feel is mostly under birded. The overhanging willows above the entrance road has certainly added to my county bird list, but there are acres of trees with no, or very difficult, access. Since I started birding there, the off-road vehicles have been banned, the vegetation has returned, and a boardwalk has been built over the lake and out to the creek mouth. Access to creek mouths that empty onto the beach has the added bonus of attracting rare shorebirds.

Every year at this time, someone will venture the question of how many rare birds were NOT seen in the thick underbrush and the vast amount of willows without access. Are we even seeing ten percent of the rare birds travelling south? It is doubtful. Often a rare bird is never refound after the initial sighting, so it is very simply blind luck that it was seen at all. It’s the thrill of the chase, though, that keeps us birders waking early to catch the first rays of the sun shining on that rare warbler.

See our county Bird Finding Guide for directions to the local areas mentioned in this article, then get out there and find a rare one.

Burrowing Owl on banner by Cleve Nash.