Some birds look dreadful at this time of year– they’ve dropped feathers and look untidy or unhealthy. But their transformation is a natural part of prepping for winter, a time to shed old, worn feathers and grow new ones for flight, insulation, and waterproofing. For birders, it’s a great time to see what’s hidden beneath the feathers, like dark skin and large ear cavities (visible behind and below the eye in the image above). While many birds lack visible external ear structures, they sport specialized feathers called auriculars which cover and protect the ear hole but allow sound to pass into the inner ear.
A fascinating aspect of bird auditory anatomy is their ability to avoid hearing loss. Unlike humans whose cochlear hair cells can sustain irreversible damage resulting in hearing loss, birds can regenerate the sensory hair cells found in their basilar papilla and recover from hearing loss. Researchers today are working to understand how these hair cells are regenerated, studying the mechanisms and the molecular triggers of hair cell regeneration, in the hopes that the same ability might be turned on in humans.