Adult sex ratios in wild bird populations

摘要: Offspring sex ratios in wild bird populations, and the extent to which they vary from equality expected by random genotypic determination, have received much recent attention. Adult (ASRs) birds, on other hand, remain very poorly described, many of questions about them posed Ernst Mayr 1939 unanswered. This review assesses population-level ratio patterns with an emphasis ASR. A quantitative assessment over 200 published estimates ASR, covering species a wide range taxa, regions habitats, supported Mayr's assertion that skewed ASRs are common populations. On average, males outnumbered females around 33%, 65% differed significantly equality. In contrast, offspring birds did not generally differ equality, mean ASR across mammal was strongly female-skewed. distortion more severe populations globally threatened than non-threatened species, previously undescribed pattern has profound implications for their monitoring conservation. Higher female mortality, rather ratio, is main driver male-skewed causes this reviewed. While may be subject number biases, discussed, there currently no evidence one male represents norm birds. better understanding reporting could contribute greatly our population processes theoretical applied research