Featured image description: Western Sandpiper to the left and two Least Sandpipers to the right. Picture taken from utahbirds.org. Photographer: Paul Higgins.
Have you ever been to a mudflat during low tide and seen flocks of tiny little birds walking around probing in the mud? If so, you have seen sandpipers. Sandpipers are tiny shorebirds that have brown upper parts and white underparts, and are found in flocks of up to hundreds or thousands of individuals. The two most common species that I have been surveying at Elkhorn Slough are the Western Sandpiper and the Least Sandpiper, and from a distance without binoculars or a spotting scope I would say they both look the same. Once I start my counts and grab my spotting scope, I can see the two different species mixed in with each other.
In order to identify both Western Sandpipers and Least Sandpipers correctly, you’ll need to make the following observations. Even though the Western Sandpiper is a tiny bird, it is a little bigger than the Least Sandpiper, has black legs, a cleaner white throat and chest, and when foraging often lifts its head higher than its shoulder. The Least Sandpiper is smaller than the Western Sandpiper, has a hooded look because its chest is not as clean as the Western and has more brown along the chest, yellow legs, and a hunched foraging style where the head stays lower than the back. Coloration on both species will change based on breeding vs non-breeding season. Once the breeding season starts in April-May, both species will become a darker brown mixed with black, but the Western Sandpiper will get more of the reddish-brown color on its head.
Next time you are out observing wildlife during low tide, grab your binoculars or spotting scope and take a closer look! You might be able to see that not all birds that are found in groups are the same.