The white necked Jacobin hummingbird lives in the tropical rainforests of Central and South America. The rainforest is a dangerous place for these little birds. Hungry predators like monkeys, snakes, larger birds, and even insects are everywhere. Biologists wondered how the tiny defenseless chicks of the hummingbird could ever survive in their nests. In 2025, an international team of researchers reported their discovery of an answer based on the work of the nineteenth century British naturalist Henry Walter Bates.
Bates studied butterfly species found in the Amazon valley. He was puzzled by a strange phenomenon. Certain unrelated species of butterflies bore an uncanny resemblance to one another. Further, these butterflies were brightly colored and would have been highly visible to predators. Bates solved the mystery. He discovered that the brightly colored butterflies contained toxins that sickened predators. The bright colors were a warning of the toxin. Non-toxic species that mimicked the warning coloration gained the same protection against predators. The phenomenon was named Batesian mimicry in his honor.
The hummingbird researchers discovered that hummingbird chicks protect themselves using their own form of Batesian mimicry. They found and monitored the nest of a Jacobin hummingbird and discovered some unusual facts about the chicks. Most hummingbird chicks are born naked, but these chicks were covered in brown feathers. When disturbed, the chicks moved with a strange jerky motion and waved their heads back and forth. By comparing notes with their colleagues, they realized that this coloration and behavior mimics that of a poisonous stinging caterpillar found in the area. The chicks scare predators away by mimicking this caterpillar.