THE SOCIAL ORGANISATION OF BEE-EATERS (MEROPIDAE) AND CO-OPERATIVE BREEDING IN HOT-CLIMATE BIRDS

摘要: Summary In the colony-nesting bee-eater Merops bulocki of northern savannas Africa males preponderate in proportion 1 -5 to female, initial breeding occurs at varying ages, and adults both sexes all age classes, particularly one-year-old males, assist pairs with nest excavation, incubation, provisioning pulli fledglings. Up three helpers can occur one nest, they may be siblings a previous year's brood. Pair-bonds are for life, bonds formed between pair their endure until next season. Some evidence suggests that other gregarious open-country species similar these respects but forest solitary-breeding savanna have sex ratio parity do not breed co-operatively. Breeding dispersion is related specific size, largest (which forage most widely) nesting densest aggregates. Other instances birds comparable social organisations briefly reviewed. The 80 involved comprise broad systematic ecological spectra about 60 them inhabit hot climates America, Australia. It suggested co-operative provides reserve experienced individuals whose recruitment permits (1) fine control stable populations non-seasonal habitats (tropical forest) within capacity food resources; (2) crude adjustment fluctuating unpredictable rainfall (Australia), enabling rapidly recuperate from depression achieve highest population level improved resources sustain; (3) regulation intermediate savannas) by either means according dictates immediate circumstances.