In an exciting first for science and bird lovers alike, researchers have discovered a baby hummingbird using a brilliant and bizarre disguise: it looks just like a dangerous caterpillar.
Jay Falk, a National Science Foundation Postdoctoral Fellow at the University of Colorado Boulder, has been studying the flamboyant White-necked Jacobin hummingbird (Florisuga mellivora) for over a decade—but only ever the adults. That changed when Ph.D. student Michael Castaño-Díaz and research assistant Sebastián Gallan Giraldo spotted something remarkable: the first-ever recorded nest of this elusive species, deep in Panama’s Soberanía National Park.
Tucked into the open cup nest was a single egg, and eventually, a newly hatched chick—sporting a fuzzy coat of long, downy feathers down its back that made it look like a venomous caterpillar. This mimicry isn’t just adorable—it’s genius. Some tropical caterpillars can sting predators or release toxins. Mimicking them may help vulnerable hummingbird chicks survive the high-risk baby bird stage.
Even more fascinating, this chick wasn’t alone in its cleverness. Another South American bird, the Cinereous Mourner, is known to use the same tactic. But aside from these two, no other bird species is known to mimic caterpillars, making them an elite and mysterious pair in the avian world.
Researchers even observed a predatory wasp approach the chick—only to be met with a defensive “caterpillar move” as the chick lifted its head and shook it in a startling display.
Nature, it turns out, isn’t just beautiful—it’s brilliantly deceptive. Falk and his team believe this disguise evolved because these hummingbirds build exposed nests close to the ground, leaving chicks vulnerable.
As scientists say, tropical forests are full of surprises—and with every curious observation, we edge closer to unlocking their secrets.
