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Yuck! Video reveals how birds share knowledge of disgusting foods—and help insects evolve

To avoid being eaten, ladybugs and other insects have evolved bright colors and markings—signals to predators that they taste foul or are toxic. But if every bird must first sample one of these bugs to discover that they’re inedible, the insects would likely vanish before their warning colors could evolve. Now, scientists report in today’s issue of Nature Ecology and Evolution that a bit of bird social learning helps the insects out. The scientists filmed a great tit opening a white paper packet stamped with a black square. Inside were bits of almond soaked with a bitter fluid. As seen in the video above, the bird pecked at the almond and almost instantly dropped the nut, shook its head, and wiped its beak repeatedly on its perch—a tit’s way of saying “yuck!” The researchers then showed the video to 15 other great tits. When these birds later foraged in an aviary containing packets stamped either with the black square or a black cross, those that had watched the film were 32% less likely than birds that hadn’t seen the video to choose packets marked with squares. Wild birds, of course, don’t watch videos to learn what’s inedible. But other research has shown they do watch each other, and are clearly paying attention when another bird says “yuck!”