Data from: Spatial, temporal and individual-based differences in nest-site visits and subsequent reproductive success in wild great tits

The behaviour of individual birds before and during the breeding period may be an important factor determining reproductive success. One commonly observed behaviour during the breeding period in many species is the visitation of multiple potential breeding sites. Much research has attempted to determine the function and consequences of this behaviour, but traditionally studies have been limited to not examining individual-level behaviour, or only considering a small number of individuals. We used automated recording of RFID-tagged birds visiting nestboxes to study a population of 80 great tits (Parus major) making >3500 daily visits across 74 breeding sites, to quantify the frequency, spatial patterning, and temporal occurrence of this behaviour from the pre-breeding period onwards. We argue that (i) the tight spatial clustering of visits, (ii) juveniles visiting more sites than adults, and (iii) males (but not females) continuing to visit other sites even as egg laying at their own nest occurs, indicate that territoriality and extra-pair mating may underpin visitation behaviour. Further, we find that spatial clustering of female visits relates to increased clutch size and fledging success, while frequently visiting a preferred nesting site increases the likelihood of obtaining a breeding site but reduces subsequent reproductive output for both sexes. Our study offers new insight into the mechanisms potentially driving breeding site visitation behaviour, and demonstrates its relationship to individual fitness. We suggest that although visitation behaviour may be related to different components of fitness, future work should use experiments to fully assess the causal factors and effects of visitation behaviour.

鸟类在繁殖期前后的个体行为，或许是决定其繁殖成功率的关键因素之一。诸多鸟类物种在繁殖期内的一类常见行为，便是造访多个潜在繁殖位点。过往诸多研究试图阐明这类行为的功能与影响，但传统研究要么未能对个体水平的行为展开考察，要么仅纳入了少量个体样本。本研究通过自动化记录佩戴射频识别（RFID）标签的鸟类访问巢箱的行为，对80只大山雀（Parus major）种群展开研究：该种群在74个繁殖位点中单日累计造访次数超3500次，以此量化繁殖前期起该类行为的发生频率、空间格局与时间分布特征。本研究认为以下三点表明，领地性与配偶外交配或许是驱动造访行为的核心机制：（1）造访行为呈现高度紧密的空间聚集特征；（2）幼鸟造访的繁殖位点数量多于成鸟；（3）雄性（而非雌性）即便在自身巢箱产卵期间，仍会继续造访其他位点。此外，本研究发现雌性造访行为的空间聚集与更大的窝卵数以及更高的幼鸟离巢成功率显著相关；而频繁造访偏好巢位虽能提升个体获得繁殖位点的概率，却会降低两性后续的繁殖产出。本研究为解析繁殖位点造访行为的潜在驱动机制提供了全新视角，并证实了该行为与个体适合度之间的关联。本研究提出，尽管造访行为或许与适合度的不同维度相关，但未来仍需通过实验研究，全面评估该行为的因果影响因素与效应。