Birds are known for their elaborate courtship rituals and romantic gestures that are replete with beautiful songs, complex dances, gift-giving practices, preening, and flamboyant plumage. While changes in colorful external attributes during this period has attracted much attention, the role of facial features remains an under-investigated aspect of this behavior.
Click here for original story, Pair-bonded Java sparrows show enlarged eye rings to signal breeding readiness
Source: Phys.org