![Portrait of a mottled brown Rock Ptarmigan looking straight on at the camera.](https://media.audubon.org/2024-09/Aud_APA-2023_Rock-Ptarmigan_A1_24848-0_Photo-Debra-Herst_0.jpg?width=233&height=200&auto=webp&quality=10&fit=crop&disable=upscale&enable=upscale&blur=100)
It’s One of the Biggest Events in a Bird’s Life. Scientists Can’t Agree How to Talk About It.
September 12, 2024 —
Every species replaces its feathers by molting, but a passionate debate among ornithologists about what to call the plumage swaps spans oceans and generations.