You may remember from the last Irregular Bird (Green Sandpiper) that the plan is to work through all the waders in the genus Tringa, the Shanks and relatives, in the order used by the IOC, below. This is the next one the Solitary Sandpiper.
It’s fairly similar to the Green Sandpiper and they were originally treated as a single species. In fact, they are easy to distinguish in flight as the Green Sandpiper has a white rump and a tail with side to side barring, while the central feathers of the rump and tail of the Solitary Sandpiper are brown creating a longitudinal stripe. These features are visible under the flight feathers in the first photo and shown in a drawing later.
In practice you can also use their ranges as the Green Sandpiper occurs in Eurasia and Africa, while the Solitary Sandpiper is an American species. It nesting range is almost entirely in Canada and Alaska. It migrates through the United States and winters in Mexico, Central America, and in northern, central and eastern South America as far south as Peru in the west and northern Argentina in the east.
I haven’t got photos of either species in flight so here is a crude drawing to illustrate the difference in flight pattern. Don’t take too much notice of anything except the different rumps, tail and length of the legs. The latter are longer and protrude farther beyond the tail in the Solitary Sandpiper. So, if you’re a dedicated twitcher, as I am now, keep a beady eye out for something special if you are in a place where either or both of these birds don’t usually occur. There are a few records of Green Sandpipers in northern Australia and a few records of Solitary Sandpiper in Siberia and Western Europe.
There isn’t much difference among the plumages of breeding adults, non-breeding adults, and juveniles though there is less streaking in juveniles and the spots on breeding adults are whiter, rather than buff and more conspicuous. I think the bird in the second photo in Trinidad is a juvenile, the one in the third photo in Brazil is an adult but I don’t know about the one in the first photo. If you’re an expert on the plumages of Solitary Sandpipers, I’d be happy to get your opinion: firstname.lastname@example.org.
Actually, I misidentified the two in Trinidad as Spotted Sandpipers in non-breeding plumage but maybe I had Spotted Sandpiper on the brain as I’d seen the one in the third photo in Tobago eleven days earlier. Non-breeding Spotted Sandpipers don’t have spots (go figure, as they say), just a little barring on the wings but they have conspicuous long white eyebrow stripes and shorter, much yellower legs, so I lack a reasonable excuse for the confusion.
Like their Eurasian cousins, Solitary Sandpipers breed in trees and shrubs using the old nests of thrushes. It so happens that the range of perhaps the commonest thrush in North America, the American Robin, overlaps the range of the Solitary Sandpiper in Canada and Alaska. The Robin, despite its name which is based on colour not taxonomy, is a Thrush and a close relative of the Eurasian Blackbird and is the most likely candidate as a provider of nests, though not much is known about the breeding behaviour of the Sandpiper.
So how does the Solitary Sandpiper get its name? Amazingly, unlike most waders which believe in safety in numbers, it migrates either alone or in small groups and often appear at stopovers or at the destination in ones or twos. It migrates mostly at night. I don’t know whether juvenile birds instinctively know where to go or whether the adults teach them. The mind boggles at what we don’t know about bird migration.
Jeff Larsen sent me this lovely photo of two birds together in Washington state, so they’re clearly not completely antisocial. He calls them Solitary Chickens, which appeals to me and he gave me permission to share this photo with you.
Solitary Sandpipers are birds of freshwater and are usually found on small ponds or in marshy areas, even in winter. We spotted the one in Brazil in a roadside pond in the Pantanal.
Next time we’ll talk about the Tattlers, two rather similar species that are next on the IOC list.