The Development of Facial Bristles in Tawny Frogmouths (Podargus strigoides)

Facial bristles are present in many avian species, although their morphology and function are still not well understood. Previous studies have suggested that rictal bristles are tactile and may play a role in nocturnal foraging, although how they develop and are used is unclear. We study here the facial bristles of the tawny frogmouth (Podargus strigoides). We describe the development of rictal bristles, alongside other developmental milestones, such as plumage and eye-opening. We note four clear stages of plumage and eye-opening and three stages of rictal bristle emergence. Chicks were born without facial bristles, and rictal bristles emerged after the eyes matured. They were fully developed only after the chick had fledged and engaged in independent feeding. This supports the suggestion that rictal bristles may play a role in independent foraging and feeding.