<P> Brood parasites are organisms that rely on others to raise their young . The strategy appears among birds, insects and some fish . The brood parasite manipulates a host, either of the same or of another species, to raise its young as if it were its own, using brood mimicry, for example by having eggs that resemble the host's (egg mimicry). </P> <P> Brood parasitism relieves the parasitic parents from the investment of rearing young or building nests for the young, enabling them to spend more time on other activities such as foraging and producing further offspring . Bird parasite species mitigate the risk of egg loss by distributing eggs amongst a number of different hosts . As this behaviour damages the host, it often results in an evolutionary arms race between parasite and host as the pair of species coevolve . </P> <P> In many monogamous bird species, there are extra-pair matings resulting in males outside the pair bond siring offspring and used by males to escape from the parental investment in raising their offspring . This form of cuckoldry is taken a step further when females of the goldeneye (Bucephala clangula) often lay their eggs in the nests of other individuals . Intraspecific brood parasitism is seen in a number of duck species, where females often lay their eggs in the nests of others . </P>

What bird lays their eggs in other birds nests