Observations of a nesting female hummingbird have revealed intriguing details about its efforts to protect its chick. The female has enhanced the camouflage of her hatchling by lining the nest with fibrous material from balsa tree seeds. Researchers observed that whenever they approached to film the nest, the hummingbird chick would lift its head and shake it side to side, fluffing its feathers in an attempt to appear threatening.
Once the researchers distanced themselves, the chick resumed its low-profile position in the nest. Questions arose about whether this behavior would be effective against real predators. The team later witnessed a wasp, known for preying on young hummingbirds, approaching the nest. In response, the chick exhibited the same defensive behavior shown to the researchers, successfully intimidating the wasp and causing it to retreat.
Falk, a member of the research team, noted that the chick’s feather configuration, color, and head movements bear a striking resemblance to moth larvae from the Megalopygidae and Saturniidae families, species native to the area. Although the chick’s appearance may not perfectly mirror any specific caterpillar, it is likely close enough to trigger caution in potential predators.
“The white-necked jacobin’s reaction to human presence and a predatory wasp seems akin to the abrupt ‘thrashing’ behavior exhibited by many caterpillars when disturbed, particularly in the same habitat,” he explained regarding the study.
…now you don’t
Alternate interpretations of this behavior are possible. The researchers propose that the long feathers resembling spines may have developed as a form of crypsis, allowing the chick to blend in with its surroundings more effectively. The balsa tree material likely enhances this camouflage further.
