Cuteness aside, though, sandpipers are pretty confusing, because “sandpiper” is both a species name and the colloquial name for the Scolopacidae family of birds. There are dozens of Scolopacidae species spanning the globe, and while close to two dozen have “sandpiper” in their names, many more don’t: godwits, woodcocks, stints, knots, yellowlegs, etc. Some sandpiper groups sound like fancy Victorian musical instruments or board games: whimbrels and willets, dowitchers, dunlins, shanks, and tattlers. Others sound like rocks: calidrids, turnstones, and curlews. And one, the phalarope, sounds like a crossbreed between Pharrell and a jackalope. (In their breeding plumage, phalaropes generally even have patches of reddish-brown feathers, the same color as Pharrell’s most famous hat.)
To further confuse the matter, sandpipers are often territorial in regard to other species, but they’re pretty chill with each other. A lot of sandpiper species nest or feed in mixed flocks, follow the same migratory paths, and interbreed. And some subsets of sandpipers have been saddled with collective names, like “peeps” (the smallest species, with the highest chirps) or “shorebirds” (which prefer coastal areas), and those names completely ignore species lines.
All of which means that if you look at a bird running back and forth at the beach and say “Hey look, a sandpiper,” there’s a really good chance that you’re right, even though that bird is technically a dunlin or a stint. Identifying specific sandpiper species induces headaches even in serious birders. (If you aren’t a birdwatcher, dropping in on a forum to watch them pore over a given sandpiper’s supercilia, mantle lines, tramlines, and coverts can be a fun lesson in vocabulary-building.)
“Piper” director Alan Barillaro says the birds in his short film are mostly sanderlings, a species of small sandpipers he encountered in the Bay Area. Like other people who can’t tell a curlew from a shank, he didn’t question their species, he just enjoyed the way the sanderlings charged down to the water as each wave receded, then fled for dry ground as each new wave arrived. He decided it’d be funny if they were just afraid of the water, and that was the beginning of “Piper.”
Sandpipers along the shore are not actually afraid of water. They just retreat from waves because their feeding methods only work in damp ground. Not all sandpiper species hang out on the coasts — upland sandpipers and buff-breasted sandpipers prefer prairies, and other species stick to mudflats or ponds — but the sanderling method of feeding is fairly common: they probe the freshly wet sand for the many small animals that move closer to the surface when the water comes in. Sandpipers tend to be voracious eaters, and they’d eat the hell out of those friendly little crabs in “Piper,” as well as any small fish, insects, snails, seeds, or eggs they found on the shore. Sandpipers are like fast-moving vacuum cleaners, collectively wiping an area clean of anything that looks edible in their patch of sand, mud, or water.
When Barillaro and his animation team started developing “Piper,” they filmed and observed sanderlings as much as possible. But since the birds are seasonal migrators that depart the Bay Area relatively early in the season, they weren’t always available for study. Like most sandpipers, sanderlings have a massive migration range, sometimes thousands of miles, depending on where they choose to settle outside of breeding season. They breed in the High Arctic tundra — the very northernmost ranges of Canada, Asia, and Greenland — but they winter along shorelines all along the United States and South America, as far south as Cape Horn. So when the sanderlings weren’t around, Barillaro and his staff studied Western sandpipers, godwits, and other relatives, which also turn up in “Piper.”
So basically, Pixar is saying a sandpiper is a sandpiper, and more detailed species analysis should be left to the experts.
Sandpiper species range widely in coloration, size, and description, and it’s hard to pin down any factoids that stretch across all the groups. So here’s a random smattering of fun stuff about specific sandpiper species:
- Red knots can eat up to 25,000 horseshoe crab eggs in a day when they’re fattening themselves up for their Arctic migration. When the eggs are plentiful, some birds get so fat that they struggle to take off, but with horseshoe crabs being harvested both as fishing bait and for their medically useful blood, red knots are now having trouble getting enough eggs to make the trip.
- The common sandpiper is only common in Europe and Asia, and in parts of Africa during winter. The American equivalent is the spotted sandpiper. Both species are known for a distinctive, nervous rocking motion called “teetering,” which earned them slang nicknames like “teeter-peep” or “jerk bird,” both of which sounds like names sandpipers would call each other on social media when they got pissed off. Female spotted sandpipers can store sperm in their bodies for up to a month before using it to internally fertilize eggs.
- Western sandpipers have spiny tongues, which they use to roll biofilm — the oozy algae scum that forms on mudflats — into little balls they can swallow. They eat by night and day, feeling their way around their feeding grounds by using their bills as sensors.
- Some sandpiper species have special nerve endings in their bills that can apparently detect incredibly minute shifts in water currents, even in sand or mud. While the sanderling chick in “Piper” watches the sand for bubbles to see where the mollusks are, real sandpipers can insert their beaks into wet ground and sense solid objects, like crustaceans, based on where the pattern of the moisture is interrupted. This ability doesn’t work on dry ground.
- Instead of running back and forth along the shore, phalaropes swim in circles to create vortexes that draw aquatic insects closer to the surface. Then they tweezer them out of the water, opening rather than shutting their bills to use surface tension between the beak surfaces to yank food along their bills and into their mouths.
According to various questionably reliable internet sources, like WhatBird.com and MyVocabulary.com, a group of sandpipers is called a “bind,” a “contradiction,” a “fling,” a “hill,” or a “time-step.” Most of these terms are ridiculous, given the way sandpipers tend to tear around like little raver marching bands, rather than piling up into hills or getting tangled up into binds. They generally don’t even contradict each other. But “time-step” is a nice term for the way they zip across the beach together. It also reminds me of the Mary Poppins musical number “Step In Time,” which has Dick Van Dyke leading a bunch of chimney sweeps in coordinated charges around the roofs of London. I am never going to be able to tell a whimbrel from a dowitcher without expert help, but at least I can follow Barillaro’s lead and imagine any sandpiper I see as a little Dick Van Dyke, just about to lead its flock in a little dance around any available chimneys. They’re practically dancing already.
Tend to cause ping-pong neck in observers
Confusing to birders
Confusing to everyone, really