What kinds of adults take on the responsibility of raising black swan cygnets? Is there an insignificant chance of #1 not being both genetic parents of the cygnets they raise?
Black swan
Up to one-quarter of monogamous black swan pairs are same-sex, with males taking over a female's nest to raise her young without her One-third of monogamous black swan pairs show extra-pair paternity, with the male aiding the female in raising another male's offspring  A cygnet is a juvenile swan
species of bird
Do black swan cygnets typically know both of their genetic parents?