[An olive-backed sunbird clings to the side of its hanging nest while it feeds chicks in the nest. After eating, one of the chicks turns around and produces a fecal sac, which the adult takes in its beak before flying away. The nest sways in the wind.] [Explore MacaulayLibrary.org]End of transcript
Nest sanitation is important when raising chicks, so rather than defecate in the nest, young birds produce a packet of waste called a fecal sac. Some parents carry this sac away from the nest before disposing of it; others simply eat it. Young birds have highly inefficient digestive systems, and the fecal sac still contains valuable nutrients for the parents.