Sandpipers and Allies: Learn to discern among sandpiper speciesMar 09, 2021 05:40PM ● By WILLIAM R. COX
The sandpiper and its allies are found in the largest family Scolopacidae of the order Charadriiformes. The 43 sandpiper species in North America have been divided into nine groups.
The taxonomy of sandpipers has been stable over the years with one change in 1950 when the short-billed dowitcher and long-billed dowitcher were split into distinct species. In Florida, the short-billed dowitcher has also been split into two races: L. g. griseus and L. g. hendersoni. The long-billed dowitcher looks almost identical to the short-billed dowitcher but is restricted to freshwater during the winter and has a higher-pitched “keek” call. The short-billed dowitcher is predominantly found in brackish or saltwater habitat with no habitat overlap in the winter, and it has a “too-too-too” call.
In North America, ornithologists determine subspecies by observing breeding of species in different areas. For example, one short-billed dowitcher breeds in Alaska, another breeds mainly east of Hudson Bay in Canada and a third from Hudson Bay west.
Species identification of sandpipers depends heavily on recognition of shorebird anatomy (body size, body areas and breeding, nonbreeding and juvenile plumages, etc.) and feather patterns such as edged, notched, fringed, tipped and subterminally banded. Identification is made more difficult by the many feather molts shorebirds experience.
Although learning to identify shorebirds is difficult, it can be learned over time with the right approach. First you must own several bird field guides. Review all the guides and select the ones that illustrate the three plumages of species. Study the text and illustrations and learn the key field marks. Note the sizes and shapes of various birds (bill size, shape and color); and study the range maps for the birds in your area. Purchase a good pair of binoculars and a spotting scope. Spend a lot of time in the field, especially with a birding club or expert in your area. Attend field trips throughout the year to learn the three different plumages of various species. Bunche Beach in Fort Myers at low tide is an excellent regional shorebird site to learn to identify shorebirds.
When I’m in the field and observe a shorebird, my workflow to identify it by species is to note that I am observing a shorebird inland in a freshwater wetland (it’s important to determine habitat). Before raising my binoculars or looking at a field guide, I keep my eyes on the bird and observe its overall size, bill size and shape, plumage and calls. For this particular bird, I know it is one of two yellowleg species. It is large with a long bill. It appears to be much larger than a killdeer and spotted sandpiper. The bill is at least 1.5 times longer than the head and is slightly upcurved. With the binoculars I see that the bill is two-toned—black at the tip and gray at the base (it’s the fall season; the bill would be all black in spring). The plumage is barred on the flanks. Its call consists of three to five loud notes. The lesser yellowlegs is the same size as a killdeer; its bill is the same length as its head, is not upcurved and is all black all year. It has no barring on its flanks, and its call is softer with fewer notes. Therefore, this shorebird is the greater yellowlegs, which agrees with the regional map and descriptions in my field guides.
When observing sandpipers over time, you will note a subtle habitat segregation among species. For example, along coastal beaches as the habitat gradient changes from the lower and deeper water’s edge to the higher and drier mudflats with herbaceous vegetation, the sandpiper species utilization is different. The dowitcher, western sandpiper and dunlin will be foraging in the water, while the sanderling feeds along the water’s edge, and the least sandpiper uses the higher vegetated areas.
When birding, please remember bird populations are declining not only in North America but throughout the world. Learn as much as you can about bird behavior and recognize disturbance behavior. All species have disturbance boundaries when being approached, depending on if they are foraging, resting, breeding or nesting. They are easily disturbed while nesting. Many shorebirds are ground nesters and will abandon their eggs or young when disturbed.
William R. Cox has been a professional nature photographer and ecologist for more than 35 years. Visit him online at williamrcoxphotography.com.