a mare used for breeding.
a young bird hatched and reared by birds of a different species as a result of brood parasitism.
a form of social parasitism practiced by certain birds, as cuckoos and cowbirds, in which eggs are laid in the nests of other birds, causing them to be hatched and the young reared by the hosts, often at the cost of the hosts’ own young.
incubation patch. a highly vascular, featherless area developed on the abdomen of certain brooding birds that is in direct contact with eggs during incubation and provides additional warmth.