Allofeeding is a type of food sharing behaviour observed in cooperatively breeding species of birds. Allofeeding refers to a parent, sibling or unrelated adult bird feeding altricial hatchlings, which are dependent on parental care for their survival. Allofeeding also refers to food sharing between adults of the same species. Allofeeding can occur between mates during mating rituals, courtship, egg laying or incubation, between peers of the same species, or as a form of parental care. Allofeeding evolved for different reasons in different species of birds. While sagebrush Brewer's sparrows allofeed to reduce predation during incubation, Sichuan jays allofeed to increase a female's nutritional level prior to egg laying, and chinstrap penguins allofeed to strengthen the bond between the pair during chick guarding. While parental allofeeding is a common form of parental care among many species of birds, the practice is not inherently restricted to biological parents and their young, and is often done for reasons unrelated to the well-being of the chicks. Arabian babblers, for instance, peer allofeed in an attempt at increasing their social rank, whereas the king penguin considers those 'non-breeders' who allofeed chicks to be altruistic and highly revered. And the far more practical barn owl, of course, peer allofeeds merely to reduce sibling rivalry/competition during meal times. Although many species of birds exhibit allofeeding, there are some species that do not perform allofeeding, such as the Siberian jay.