Four plovers of the Bay Area
By Linda Carloni
One of the (many) great things about the City of Alameda is the birding. Our long sandy bay-side beach and mudflats offer a feast of winter shorebirds. Among my favorites are our four plovers.
Plovers are in the family Charadriidae – chunky small-to-medium-size shorebirds with short necks, large eyes, and relatively short bills. Unlike their sandpiper colleagues, they are visual feeders. As you watch them, they run, stop, and then peck to get their prey. Their shorter bills don’t allow them to probe effectively to find and devour their food, so they occupy a different feeding niche. Their large eyes let them forage in low-light conditions, even at night.
Of the Bay Area’s four plovers, the Killdeer is with us year-round. While it does share our beaches, it seems to prefer plowed fields, gravelly patches, and other human-altered areas. Killdeer parents are well known for their distraction display – feigning injury and calling loudly in a visible location to draw a predator away from the nest. When the predator is far enough from the nest, the performing Killdeer makes a quick recovery and flies away, returning later to the nest. Like the Snowy and Semipalmated Plovers, it is brownish-tan on top and white below. Distinctively, it has two full dark neck rings. Its loud “kill-deeeeeer” alarm call lets us know how it got its name.
Killdeer: Note the double neck ring / Photo by Bob Lewis
Semipalmated Plover: Note the single neck ring / Photo by Bob Lewis
Unlike the Killdeer, the Semipalmated Plover joins us in the autumn; some stay for the winter, while others migrate further south. They leave us during spring and summer to breed in the north. Both the Killdeer and the Semipalmated have “disruptive coloration,” striking patterns that break up the silhouette of the bird – in the Semipalm’s case, one full dark neck ring.
These field marks help us distinguish one species from the other, but also make it more difficult for predators to see the bird as a whole against a variegated background. The Semipalmated Plover seems to be among the few plovers whose numbers are increasing, perhaps due to its versatility in food and habitat choice, its widespread coastal winter distribution, or its habitat expansion in the sub-Arctic.
The Snowy Plover is a much smaller, lighter, and whiter version of the first two. It’s only about 6 inches long, compared to about 7 inches for the Semipalm and a whopping 8 to 11 inches for the Killdeer.…