Data from: Determinants of male floating behaviour and floater reproduction in a threatened population of the hihi (Notiomystis cincta)

Floating males are usually thought of as non-breeders. However, some floating individuals are able to reproduce through extra-pair copulations. Floater reproductive success can impact breeders’ sex-ratio, reproductive variance, multiple paternity and inbreeding, particularly in small populations. Changes in reproductive variance alter the rate of genetic drift and loss of genetic diversity. Therefore, genetic management of threatened species requires an understanding of floater reproduction and determinants of floating behaviour to effectively conserve species. Here, we used a pedigreed, free-living population of the endangered New Zealand hihi (Notiomystis cincta) to assess variance in male reproductive success and test the genetic (inbreeding and heritability) and conditional (age and size) factors that influence floater behaviour and reproduction. Floater reproduction is common in this species. However, floater individuals have lower reproductive success and variance in reproductive success than territorial males (total and extra-pair fledglings), so their relative impact on the population's reproductive performance is low. Whether an individual becomes a floater, and if so then how successful they are, is determined mainly by individual age (young and old) and to lesser extents male size (small) and inbreeding level (inbred). Floating males have a small, but important role in population reproduction and persistence of threatened populations.

人们通常认为游荡雄体不参与繁殖活动。然而，部分游荡个体可通过婚外配（extra-pair copulations）实现繁殖。游荡个体的繁殖成功率会对繁殖种群的性比、繁殖方差、多重父权及近交水平产生显著影响，在小型种群中该效应尤为突出。繁殖方差的改变会直接影响遗传漂变的速率与遗传多样性的丧失速度。因此，对濒危物种开展遗传管理工作时，需明晰游荡个体的繁殖特征及其游荡行为的决定因素，方能达成有效的物种保护目标。

本研究以具有完整系谱记录的野生濒危新西兰特有鸟类hihi（学名：Notiomystis cincta）种群为研究对象，旨在评估雄性繁殖成功率的方差，并检验影响游荡行为与繁殖表现的两类因素：遗传因素（近交与遗传力）以及条件因素（年龄与体型）。

该物种中，游荡个体的繁殖现象较为普遍。但相较于领域雄鸟（无论总繁殖后代数还是婚外配产生的离巢幼鸟数），游荡个体的繁殖成功率及繁殖方差均更低，因此其对种群整体繁殖表现的相对影响较为有限。

个体是否会成为游荡者，以及若成为游荡者后的繁殖成功率高低，主要由个体年龄（幼年与老年阶段）决定，其次受雄性体型（小型个体）与近交水平（近交个体）的小幅影响。

游荡雄体在濒危种群的繁殖与种群存续中虽作用规模有限，但仍具有不可忽视的重要意义。