Border incidents: swimming shorebirds; the case of the Spotted Redshank
Shorebirds do what their name implies; they generally keep to the shore. There are a few exceptions our Pied Avocets swim well and often, and of course the phalaropes have taken this trend all the way: they obtain most of their food swimming in the nesting period, and even become seabirds on the open ocean in winter. But our oystercatchers, plovers, sandpipers, turnstones, curlews, godwits and ‘shanks’ usually don’t swim, even though some species habitually forage in belly deep water, as f. ex. the Curlew Sandpiper. They are all able to swim, but do so only in special circumstances, f. ex. when fleeing a predator or when inadvertently landing in too deep water. I’ve seen a young Oystercatcher dive into deep water when pursued by a raptor, and I have several times seen Red Knots been forced to swim, when they landed in just too deep water, landing together with their frequent companions the Barred Godwits, that have just a little longer legs. Greenshanks chase shrimps now and then in quite wild pursuit, and once I saw one blundering into deeper water and swimming for some seconds, before flying up.
But there is , to my knowledge—which is quite restricted– just one species of shorebird, that habitually not only swims, but also upends, and even executes short dives, and that is the Spotted Redshank Tringa erythropus. This species is easily recognized in summer, when it is almost entirely black (it is called Sotsnipe= sooty snipe in Norwegian, and Zwarte Ruiter= black ‘shank’ in Dutch), but it nests far north (Tromsø, where I live, is still too far south and west); in the eastern part of Finnmark the species is a quite common nesting bird on marshy areas, often near lakes . I have seen alarming parent birds scold from the tip of a pine tree, for so to fly down and land in the middle of a small lake , where they swim quite complacently, before flying effortlessly up again, and resuming their scolding.
Here in Tromsø Spotted Redshanks are , together with Common Redshanks (also very common nesting birds locally) and Ruffs, common autumn migrants in late summer and early autumn. They are usually not on the open shore, but in lagoons or brackish pools close to the shore, and also here I have seen them swim quite regularly and also forage this way, stretching their necks under water, and now and then upending like dabbling ducks, although for shorter periods. Earlier, in the years 1963-65, when I was a zoologist at the Delta Institute in Yerseke, the Netherlands, and i.a. conducted regular waterfowl counts in many of the brackish creeks in the SW Netherlands, the area where I grew up, I have watched swimming Spotted Redshanks quite regularly, also upending and a few times even executing shallow and fast dives. I do not know what they chased there.
In 1988 I visited India in late autumn and in an open roadside pool near Bharatpur I watched a group of c 20 Spotted Redshanks apparently feeding by swimming around like large phalaropes, upending (‘more quickly and nervously than dabbling ducks’, my notes say). Also here I twice saw a short dive.
The propensity of Spotted Redshanks for swimming, more than other shorebirds, has been noted several times in the literature, so my observations bring nothing new. But the difference with the other Tringa species, many of which I have also watched for longer periods (less so the nearctic species, although I can proudly note that back in 1963 I found the first Lesser Yellowlegs for the Netherlands). I would therefore be most grateful for observations of swimming shorebirds, both of the Spotted Redshanks themselves , but especially also of other species.
Wim Vader, Tromsø, Norway
