Data from: Not all who wander are lost: Prospecting and settlement of male floaters in the spotless starling

Floaters are non-breeding individuals that lack a territory or a breeding
site. In many species, they can be seen visiting the territories of
conspecifics before obtaining their own breeding site. Prospecting
behavior is hypothesized to benefit floaters through information
acquisition, enhanced site familiarity and dominance over other floaters.
Here, we used detections of PIT-tagged male floaters in a population of
spotless starlings (Sturnus unicolor). We investigated how floater
activity varied across breeding stages and how their visits influenced
subsequent nest site selection. We also tested whether distance,
reproductive success, and phenotype and fate of the former owner
influenced final settlement. We found that floater activity increased
during the nestling-rearing period as nestling age increased. Floaters
were more likely to breed near the area where they had been detected the
previous year, suggesting that prospecting allows males to secure a
foothold in their future settlement area. Although prospecting was higher
in nests with a higher number of nestlings, neither breeding success,
phenotype, nor provisioning rate of the last owner were related to nest
choice, suggesting that public information is not used by males to decide
where to settle. However, we found that floaters were more likely to breed
in nest boxes where the previous owner had disappeared from the colony,
suggesting that visits by male floaters in this species allow them to
detect new vacancies. Our results suggest that prospecting might serve
several non-mutually exclusive functions. Further studies in non-saturated
colonies could shed light on the functional aspects of prospecting.

漂泊个体（floaters）指无领地或繁殖位点的非繁殖个体。在诸多物种中，这类个体在获得自身繁殖位点前，常会造访同种个体的领地。现有假说认为，探勘行为可通过信息获取、提升对繁殖位点的熟悉程度以及确立相对于其他漂泊个体的优势，使漂泊个体获益。本研究基于纯色椋鸟（Sturnus unicolor）种群中被动集成应答器（PIT）标记的雄性漂泊个体的检测数据展开分析，探究了漂泊个体的活动随繁殖阶段的变化规律，以及其造访行为对后续巢址选择的影响。此外，本研究还检验了空间距离、原巢主的繁殖成功率、表型及命运是否会对最终定居位点产生影响。研究结果显示，漂泊个体的活动强度在育雏期随雏鸟日龄增长而升高。漂泊个体更倾向于在上一年被检测到的区域附近繁殖，这表明探勘行为可帮助雄性个体在未来的定居区域站稳脚跟。尽管雏鸟数量更多的巢箱的探勘频次更高，但原巢主的繁殖成功率、表型及育雏率均与巢址选择无关，这表明雄性个体并未利用公共信息来决定定居位点。然而，本研究发现，漂泊个体更倾向于在原巢主已离开繁殖群的巢箱中繁殖，这表明该物种的雄性漂泊个体通过造访可发现新的繁殖空位。本研究结果表明，探勘行为可能兼具多种非互斥的功能。后续可在非饱和繁殖群中开展相关研究，以进一步阐明探勘行为的功能机制。