The adaptive significance of off-lek sociality in birds: A synthetic review, with evidence for the reproductive benefits hypothesis in Long-wattled umbrellabirds

Anecdotal evidence suggests that lekking birds exhibit considerable variation in form and degree of sociality away from the lek, yet this phenomenon has received very little theoretical or empirical research attention. Here, we provide the first synthetic literature review of off-lek sociality in birds and develop a conceptual framework for the potential adaptive function of off-lek sociality across lekking taxa. We then present a case study of the Long-wattled Umbrellabird (Cephalopterus penduliger), where we find support for the hypothesis that off-lek sociality is primarily driven by male reproductive incentives for coordinating lek attendance during the breeding season. During periods of high lekking activity, male umbrellabirds depart the lek in highly coordinated groups and maintain larger off-lek social groups relative to periods of low lekking activity. These seasonal differences in off-lek sociality do not occur in females, are not explained by patterns of foraging behavior, an..., ,轶事证据表明，求偶场（lek）鸟类在离开求偶场后的社交形式与社交程度存在显著差异，但该现象尚未受到足够的理论与实证研究关注。本研究首次针对鸟类的求偶场外社交行为开展综合文献综述，并构建了适用于各求偶类群的求偶场外社交行为潜在适应功能概念框架。随后，本研究以长肉垂伞鸟（Cephalopterus penduliger）为案例对象，验证了如下假说：求偶场外社交行为主要由雄性在繁殖季协调求偶场出勤的繁殖动机所驱动。在求偶活动旺盛期，雄性伞鸟会以高度协同的群体离开求偶场，且相较于求偶活动低迷期，其求偶场外社交群体规模更大。这种求偶场外社交的季节性差异仅存在于雄性个体中，且无法用觅食行为模式加以解释，……