White-necked Jacobin hatchlings look and move like poisonous caterpillars, potentially warding off predators
For the first time, scientists have documented a hummingbird chick that may mimic a poisonous caterpillar to dissuade hungry predators. In 2024, researchers stumbled upon a one-day-old white-necked Jacobin chick (Florisuga mellivora) in Soberanía National Park outside Panama City, Panama. The baby bird was covered in long brown feathers, which at this point appeared like the hair of several poisonous caterpillar species in the region that can be dangerous or even lethal to predators. When approached, the chick wagged its head back and forth in the same way that many caterpillars do when threatened. As most hummingbirds hatch naked, researchers were surprised to see the chick covered in feathers. They were also surprised to see the shaking behavior, which researchers hadn’t previously reported in any other hummingbird species. “We know so little about what nesting birds do in the tropics,” said Jay Falk, the paper’s first author and a postdoctoral researcher at the Smithsonian Tropical Research Institute and University of Colorado Boulder, in a press release. “But if we put more effort into observing the natural world, we might discover these kinds of behaviors are very common.”
Read more at CU Boulder Today.
