It was one of those miserable hot August days. The only upside, if it can be called that, was that the water levels at Hoover Reservoir had been dropping and exposing some mudflats. (Note: With Columbus’ increased growth, the Water Department doesn’t let this happen much anymore.) That’s good shorebird potential, and we slogged out to take advantage of it, finding nothing but Killdeer at first. Then we spotted a little sandpiper standing at the water’s edge, and thought, “Oh crap, it has few markings and we’ll have to inch out onto the mud to get closer.” As we started to creep out, the bird flushed, showing a strange stiff-winged flight and uttering a sharp two-note cheep. “Spottie!” we cried, almost in unison, visually following it until it landed and gave the distinct bobbing walk that clinched the ID. Never did we feel so relieved, as the mud was deep and our shorebird ID skills were a bit rusty. This episode has almost certainly happened to most birders at sometime in their lives. Saved by a Spottie.
Spotted Sandpipers, for some reason known only to God, got more than their fair share of unique field marks when they were handed out to the shorebirds. Rather than subtle shadings of legs or tertials, they managed to grab a spotted chest (breeding plumage only), yellowish to pinkish legs, a teetering gait, and a stiff-winged flight. This combination of marks and behaviors makes it easier to ID them than most small sandpipers. The behaviors make their ID especially quick, which can be a blessing if you have a flock of other shorebirds to sort through.
Spotties are iconoclasts among shorebirds. They regularly breed on streams, a habitat not favored by their brethren, and they breed much further south. They breed here in Ohio, even, being found along streams or around wetlands through out the state. This is apparently due to their ability to snag insects along the water’s edge. If you watch them for any amount of time, you’ll see that they’re much more adaptable than other sandpipers. Instead of a life of ‘probe-probe-probe’ or ‘pick-pick-pick’, Spotties run around and do a little of everything: probe, pick, teeter, dash and snap, as is nicely shown in the video below. This wide-range of foraging apparently allows then to adapt to many shorelines.
Spotties are weird in some more surprising ways as well. Females are the more aggressive, territorial birds, often showing more spotting and color (pinkish legs and bills) during the breeding season. Males are the homebodies, incubating the nest and feeding the youngsters – mostly leading them around and showing them what to do, as the young are precocial. In extremely productive (read – buggy) environments, females will even take multiple mates, leaving each with a clutch of eggs to raise. The scientific hypothesis behind this behavior, called polyandry (as opposed to polygamy), is that females have to produce relatively enormous-sized eggs to hatch precocious chicks, so it pays them to focus on egg production (eating bugs and defending the territory) rather than incubation and caring for the young.
Now, about that teetering. Spotted Sandpipers can’t help but teeter – they do it when they land, they do it when they walk, they do it excessively when they’re excited. It’s an innate behavior – even Spottie chicks do it shortly after they start running around, as seen in the very cute video below. Other insect-eating birds of streams and rivers also do it to some extent – Solitary Sandpipers, Common Sandpipers of Eurasia, Northern and Louisiana Waterthrushes, and Buff-rumped Warblers of central and South America. One hypothesis is that they use the motion to scare up insects along the shoreline, since that’s their major food source in these habitats. Another is that it’s a visual link between pairs in this noisy habitat. We just don’t know, but it still makes Spotties a lot of fun to watch.