Chapter eight looks at how birds communicate and socialize. Most birds practice monogamy for breeding, but genetics studies have shown that while birds may be socially monogamous, genetically they may not. Other birds practice various form of polygamy. There are also many ways birds attract mates, from songs and bright colouration, to dance and building architecture. Mating choice also depends on how genetics affects the performance of birds. Birds may be solitary or group together, possibly with other birds, giving rise to a social hierarchy that is still being studied. These groups may also be a way to spread information, like ways to get food, in interesting ways. Finally, birds can form mutualism with other animals for common benefit. Social living is not without problems, like the spreading of diseases.