Western Sandpiper at Mission Bay

Western Sandpiper showing semipalmated toes. Mission Bay, San Diego, California. February 16, 2015. Greg Gillson.

On the East Coast, one of the most abundant little shorebirds of the beaches and tidal flats in migration is the Semipalmated Sandpiper. This species is decidedly rare on the West Coast, though annual in small numbers.

Instead, we on the West Coast have two similar small shorebirds. The Least Sandpiper is the smallest of the "peeps" (so named for their peeping calls). The Western Sandpiper is larger, but only 6-1/2 inches long from bill tip to tail tip.

As you might guess from the name, Semipalmated Sandpiper has something called semipalmations. What are those? Partial webs between the toes. It is similar to the flap of skin between your thumb and forefinger.

However, the Western Sandpiper also has semipalmated toes, as you can see in the photo above. Many other shorebirds do too. Scientists who name birds aren't always the most original.