 The benefits of cooperative breeding in birds have been well-documented.One example is the azure-winged magpie ("Cyanopica cyanus"), in which studies found that the offspring's cell-mediated immune response was positively correlated with increase in the number of helpers at the nest.Studies on cooperative breeding in birds have also shown that high levels of cooperative breeding are strongly associated with low annual adult mortality and small clutch sizes, though it remains unclear whether cooperative breeding is a cause or consequence.