Swainson’s Thrush - Strangest Bay Area Bird Call of All!

July 7, 2007 on 4:03 pm | In Daily Local Birder |

Greetings, birders!

Have you had the strange feeling that you’ve been being followed by a pint-sized vehicle with an infinitesimal, buzzy car alarm since spring arrived in the Bay Area? Brace up! Tiny aliens with bitty noisemakers have not taken over the planet, nor are you going crazy. Chances are, Swainson’s Thrush is lurking in the underbrush nearby.

This fantastically secretive bird stops people in their tracks each year when it arrives from the south for the warm season and begins sounding its other-worldly song. The musician’s ear detects a couple of grace notes followed by an ethereal series of rising triplets, all rendered in a most unusual, wheezy, electronic-sounding voice. We honor this unique wild bird with having the very strangest of all calls in the San Francisco Bay Area.

As my illustration of Swainson’s Thrush, Catharus ustulatus, shows, this is a somewhat plain looking bird with a dusty top half and spotted breast. Pacific coast birds are ruddier than inland ones, but the overall appearance of this fowl is sedate when compared to his relative, the brilliant orange and black Varied Thrush who was with us in the winter. Nevertheless, we absolutely love this fine wild bird, and only wish we could catch more than a glimpse of him in his hiding places beneath thick hedges, generally near a body of water. He is one of Sonoma County’s most reclusive inhabitants.

Swainson’s Thrush measures, on average, 7″ from his strong beak to his tail. He has a prominent cream colored eye ring and a very soft, blurry look to his plumes. He forages on the ground for both insects and berries and builds a cup-shaped nest of twigs, leaves, roots and moss. 3-5 blue eggs are typical of this bird. The birds maintain a very small territory, making it possible for the birder to be surrounded by serenading male Swainson’s Thrushes in a single large yard or on a short creekside path.

My husband and I had our first encounter with Swainson’s Thrush at Willowside Rd. creek in Santa Rosa, CA. I clearly remember the sweltering hot day, and the two of us going up and down, up and down the path trying to figure out where that crazy noise was coming from. We never saw the bird and were driven almost to distraction by his persistent, mysterious fanfares. Thankfully, our bird songs DVD solved the problem for us when we got home and we immediately recognized the the sound that had so baffled us by the stream.

I have not heard a single Swainson’s Thrush in the Sonoma Valley area of Sonoma County. Perhaps their habitat has been destroyed by the monotonous vineyards that leave no hedges or trees for birds to make their homes in, or perhaps this thrush simply doesn’t like the layout here. West Santa Rosa seems to be a good place to go, locally, to find Swainson’s Thrush, and the Willowside Road area almost guarantees the sound, if not the sight, of one.

However, if you want to get to Swainson’s Thrush heaven, simply drive out to West Marin County, to the Point Reyes National Seashore area. The parking lot at Heart’s Desire beach should be renamed Swainson’s Thrush Official Headquarters. There must be thousands of these birds in this area and it is simply amazing to listen to them, and to try to spot one in the bracken. In addition to their rising mechanical call, they also give a single flute-like note frequently. Mornings and evenings are the best time to attend this free concert by the sea.

*An important hint on identifying Swainson’s Thrush: if you see a bird that looks very much like my sketch, but it is out in the open, going about its business, chances are, you may be seeing a Hermit Thrush, Catharus guttatus. The Hermit Thrush is seen most often in the winter here in Sonoma County, but some are year-round, so that’s not a definite help. What does help me is to look at the tail of the bird. The Hermit Thrush’s tail tends to be an extremely vivid cinnamon color. But, for a positive ID, you do need to hear the songs. Swainson’s call rises, but the Hermit’s call, though quite similar in its electronic sound, just twirls around in one place rather than going up or down. The Kenwood/Glen Ellen area is an excellent place to look for Hermit Thrushes and despite their shy sounding name, they are much more extroverted than the Swainson’s Thrush, in our experience.

Swainson’s Thrush is proof that you must never judge a bird by it’s ‘cover’. Who would ever guess that this sedate looking fellow would be such an audacious caroler? He is just one of the many fascinating oddities that keep us always birding, always in a state of awe over the varied wonders of the bird world.