Shoreline Lake and Vicinity (Mountain View, CA)
On Christmas Eve, I spent the morning birdwatching at Shoreline Lake, the Coast Casey Forebay, and the adjoining areas of Salt Pond A1 and Charleston Slough in Mountain View, CA. This area is renowned for its bird life, especially during the winter months, when it is often inundated by hordes of waterfowl, shorebirds, and other refugees from North America’s icier northern latitudes. It was a bright, calm, sunny morning for this visit, one of those bitingly beautiful winter mornings where the sky is an intense blue and the wisps of cirrus trailing across it are an intense white and the air is cold enough to turn your breath to steam.
Shoreline Lake was my first destination, and although it was a bit light on waterfowl, I did spot several pairs of Common Goldeneyes (Bucephala clangula) there, associating closely as they dove after the lake’s population of small fish. The males would frequently try to impress their mates by pointing their beaks straight up and flashing their wings in a striking courtship display. Here and there, a few female Buffleheads (Bucephala albeola) mingled with the Goldeneyes; they were, oddly enough, unaccompanied by any males. Elsewhere on the lake, a loose flock of about a dozen Eared Grebes (Podiceps nigricollis) zigzagged their way across the lake in search of prey, their bright red eyes glinting sharply in the morning sunlight.
Around the lake, a variety of trees, shrubs, and undergrowth provided cover for a variety of wintering sparrows and other passerines. Most notable for me was the pair of Fox Sparrows (Passerella iliaca) whom I found vocalizing loudly in the shrubs at the northwestern tip of the lake. I had not seen this species in quite a while, so it was good to reacquaint myself with it. Also present here were a few Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), California Towhee (Melozone crissalis), White-crowned Sparrows (Zonotrichia leucophrys), Golden-crowned Sparrows (Zonotrichia atricapilla), Ruby-crowned Kinglets (Regulus calendula), American Robins (Turdus migratorius), and Hermit Thrushes (Catharus guttatus) – the last two feeding on a heavy crop of bright red pyracantha and cotoneaster berries.
A short walk north from the lake took me to the western tip of Salt Pond A1, where I found my only Gadwall (Mareca strepera) of the visit, flying just above the pond’s surface. He landed close to a pair of Northern Shovelers (Spatula clypeata), who seemed a bit perturbed by his sudden appearance. Further off in the distance, large rafts of Ruddy Ducks (Oxyura jamaicensis) floated on the pond’s surface, most of them sound asleep.
A small levee separated Salt Pond A1 from Charleston Slough, where an observation deck looked out onto the slough’s expanse of blue-gray water. From this platform, I spent time observing and photographing the many Northern Shovelers and Canvasbacks (Aythya valisineria) that had gathered there that morning. Overhead, a half dozen Tree Swallows (Tachycineta bicolor) flitted through the brilliant sky; although most Tree Swallows spend the winter in Southern California and Mexico, a few of them always seem to forego that trip and spend the winter here.
My final stop of the morning was the Coast Casey Forebay, where I was momentarily mesmerized by the striking black-and-white pattern of some 400 American Avocets (Recurvirostra americana) in flight. They swirled through the air above the forebay like water swirling about inside a cup; then they landed – almost all at once – on the mudflats at the west end of the forebay. Surrounding them there were swarms of Northern Shovelers, Ruddy Ducks, Black-necked Stilts (Himantopus mexicanus), Least Sandpipers (Calidris minutilla), and Long-billed Dowitchers (Limnodromus scolopaceus). Scattered amongst these birds were small groups of gulls – mainly California and Ring-billed Gulls (Larus californicus and Larus delawarensis, respectively), plus a noticeably smaller gull with a rather tiny bill. After studying this smaller gull for a bit, I realized that it was a Short-billed Gull (Larus brachyrhynchus), which was known as a Mew Gull until 2021, when it was split from the Common Gull of Eurasia and officially renamed. This was another species that I had not seen in a while, so it was good to re-familiarize myself with it.
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