Contact: Science Press Package Birds defy gravity to eat
Have you ever wondered how some birds with long beaks eat and drink" Well, researchers have discovered a new way that some shorebirds get their food, and it’s more complicated than you might have thought!
A bird called a phalarope starts a meal by swimming in fast, small circles on the surface of the water. This motion creates a sort-of whirlpool that pulls small crustaceans and other invertebrates up to the surface, within its reach. The phalarope will then peck its beak at the swirling water to capture small droplets of water and the tiny organisms contained inside them. But because of the shape of its beak, the bird cannot suck the water all the way up to its mouth. So what it does instead is quickly open and close its beak many times like a pair of tweezers, and the water actually moves up the long beak — against the pull of gravity — and all the way to the phalarope’s mouth. This incredible action is made possible because of the unique properties that water has, and in particular, something called “surface tension.” Surface tension is responsible for many of the interesting things that water can do. For example, surface tension is what allows water to move upward to the tops of trees. It also allows some insects to breathe underwater, and others to walk on top of it. In general, surface tension is what makes water “elastic” or “sticky” sometimes. So when the phalarope opens and closes its beak like tweezers, the water is able to move up its beak toward the hinged end where the bird’s jaws meet. This is the first time that scientists have documented this particular way of eating. But since the discovery, researchers have created mechanical beaks of many different sizes to test how effective this “tweezer” motion is in moving water “uphill.” So far they have found that by changing the size of the beak, they can move the water at different speeds, and that certain beaks are better for the job than others. ###
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