Among these East African birds only one pair of each flock breeds while the rest assist in raising the chicks. Phoeniculus purpureus begin their breeding activity in May or June, a few weeks after the start of the rainy season. Abnormal rainfall reduces the main food supply, the larvae of moths that inhabit the woodland. This leads to a high death rate. Woodhoopoe compete for roost holes with other birds, bees and mammals. The available roost holes determine the distribution of the flocks. Genets Genetta genetta and driver ants raid the roosts at night, killing some of the birds. The death rate is highest among breeding males. Subordinate males frequently outlive their dominant allies and inherit breeding status. An older helper may emigrate to take advantage of a territorial breeding vacancy. He will usually be accompanied by one or more younger subordinates.