Birds can experience color changes through several mechanisms:
- Seasonal molting, where new feathers may have different colors
- Wear and sun bleaching of existing feathers
- Diet-dependent changes, especially for carotenoid-based colors
Many birds display different colors during breeding and non-breeding seasons. For instance, male American Goldfinches transform from bright yellow in summer to dull olive-brown in winter. However, birds cannot actively change their feather color like chameleons – any change requires either new feather growth or environmental factors affecting existing feathers.