This Fuzzy Hummingbird Chick May Be in Disguise—as a Caterpillar

In March 2024, biologists in Panama discovered a remarkable example of mimicry while observing a white-necked jacobin hummingbird nest. Upon hatching, a chick displayed long, downy feathers and behavior that made it resemble a venomous caterpillar. The chick not only looked insect-like but also mimicked a caterpillar’s defensive head-flicking movements when approached—behavior known to deter predators. This may be a rare case of Batesian mimicry, where a harmless animal mimics a more dangerous one to avoid predation.

The mimicry proved effective when a wasp flew by and quickly retreated after the chick’s caterpillar-like motion. Such mimicry is extremely uncommon in birds, with only one other known example—the cinereous mourner’s chick in the Amazon. Researchers believe the jacobin’s exposed nest locations, atop large leaves rather than hidden sites, may have driven the evolution of this protective adaptation. The finding adds a rare and fascinating instance of cross-species mimicry to avian biology.