This amazing hummingbird chick looks like a caterpillar
Watch this video on white-necked jacobins, a hummingbird species whose chicks look like caterpillars.
A hummingbird chick that looks like a caterpillar
A team of scientists from the University of Colorado Boulder were studying white-necked jacobin hummingbirds in Panama when they made an interesting discovery. They said on March 17, 2025, that the newborn chicks of this hummingbird species appear to be born with long, thin, yellowish feathers on their backs. This plumage resembles the hair that surrounds caterpillars. Coincidence? Scientists think not. It appears to be a defense mechanism for these tiny birds’ wee chicks.
The scientists published their peer-reviewed findings in the journal Ecology on March 17, 2025.
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The discovery begins with Jay Falk, a U.S. National Science Foundation postdoctoral fellow working at the University of Colorado and at the Smithsonian Tropical Research Institute (STRI). Falk was studying adult white-necked jacobins (Florisuga mellivora) in Panama. This is a neotropical hummingbird species that lives in southern Mexico, Central America and northern South America, in countries such as Brazil, Peru and Bolivia. The species also lives in Trinidad and Tobago.
Falk has studied this species for over a decade, but only adult hummingbirds. Then, co-authors Michael Castaño-Díaz and Sebastián Gallan Giraldo, a PhD student and a research assistant also working at STRI, spotted a hummingbird nest with an attentive mother caring for her egg. This caught the scientists’ attention, so they told Falk.
Observing the nest
Since this was the first white-necked jacobin nest scientists had seen so far, they decided to visit it every day to check on its progress. They also enlisted videographer Joe See to record the events that followed.
About 18 to 20 days later, the egg hatched, and the scientists saw something spectacular. The tiny chick had long, fluffy feathers on its back. This made the newborn hummingbird look like a dangerous caterpillar.
A new strategy to scare off predators?
And why is a caterpillar dangerous? Because some caterpillars have a hairy covering that causes painful skin reactions. One of the most obvious symptoms is hives (itching). In some humans, contact with this hair even causes headaches, nausea and fever.
So, is this cute little hummingbird also dangerous? Nope! Apparently, this creature disguises itself as a caterpillar, but its feathers don’t provoke skin reactions like the hairy coverings of caterpillars do.
The researchers also observed that the nest was covered with hairy-looking tree seeds. These are the local balsa trees (Ochroma pyramidale). This suggests that these hummingbirds use this strategy to camouflage themselves.
The scientists also observed another curious fact. A carnivorous wasp approached the chick, and the newborn began to move its head, as some caterpillars do when a predator is nearby. It seems that this imitation serves the chicks as a method of protection against predators.
Are other hummingbird species born with this characteristic?
The scientists looked for photos of other similar newborn animal species to verify how special this characteristic is. The cinereous mourner (Laniocera hypopyrra), endemic to South America, also begins life with feathers that look like caterpillar hair.
However, most hummingbird species are born without these distinctive feathers.
It’s not surprising that this species has developed this mimicry or camouflage ability. White-necked jacobins build their nests open, that is, in a cup shape. They also place them on exposed branches close to the ground. This makes them easy prey.
Scientists believe this species has evolved to the point of mimicking caterpillars and thus protecting itself from potential predators. However, to support these hypotheses, they’ll need to observe more individuals.
Bottom line: The white-necked jacobin hummingbird might be small, but it has an interesting form of protection. This species is born with feathers similar to dangerous caterpillar hair.
Source: Potential caterpillar mimicry in a tropical hummingbird
Via University of Colorado Boulder
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