Parejo Deseada, White Joel, Danchin Etienne
Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Aridas, C.S.I.C., C/ General Segura, 1, 04001, Almeria, Spain.
Naturwissenschaften. 2007 Sep;94(9):749-57. doi: 10.1007/s00114-007-0253-z. Epub 2007 May 9.
Dispersers are expected to assess breeding habitat quality before settlement. Although cues reflecting habitat quality are well studied, social cues have not been as well evaluated. In this paper, we studied breeding habitat selection during 3 years in a natural population of blue tits, Cyanistes caeruleus, breeding in nest-boxes. Our aim was to investigate if this species used conspecific density and/or reproductive success of con- and heterospecifics (i.e., social cues) in settlement decisions. The patterns observed were consistent with the idea that juveniles, when dispersing from their natal patches, did not react to any of the cues that we tested. In contrast, breeders that dispersed seemed to respond to both conspecific mean patch reproductive success (PRS) and breeding density of the settlement patch in the year of dispersal, their response differing according to their own reproductive success. Indeed, failed breeders moved to areas with high PRS and low density relative to source patches, while successful breeders behaved the opposite. The comparison between juveniles and adults might be modulated by the limited time available to juveniles to gather information on PRS and density at the end of the dispersing year. Adults lacking these time constraints, however, seemed to rely on these conspecific cues although limited by their own quality. Additionally, breeders were more likely to be immigrants in patches with relatively low breeding success and density the previous year, suggesting that settlement is influenced by multiple cues, which may reveal information on different aspects of habitat and be available at different moments. Collectively, our results support the importance of social cues for blue tits' settlement.
预计扩散者在定居前会评估繁殖栖息地质量。尽管反映栖息地质量的线索已得到充分研究，但社会线索尚未得到同样充分的评估。在本文中，我们对三年间在巢箱中繁殖的蓝山雀（Cyanistes caeruleus）自然种群的繁殖栖息地选择进行了研究。我们的目的是调查该物种在定居决策中是否利用了同种和异种的同种密度和/或繁殖成功率（即社会线索）。观察到的模式与以下观点一致：幼鸟从出生斑块扩散时，对我们测试的任何线索都没有反应。相比之下，扩散的繁殖者似乎对扩散当年定居斑块的同种平均斑块繁殖成功率（PRS）和繁殖密度都有反应，它们的反应因自身繁殖成功率而异。事实上，繁殖失败的个体迁移到相对于源斑块而言繁殖成功率高且密度低的区域，而繁殖成功的个体则表现相反。幼鸟和成年鸟之间的这种差异可能是由于幼鸟在扩散年结束时收集关于PRS和密度信息的时间有限。然而，不受这些时间限制的成年鸟似乎依赖这些同种线索，尽管受到自身质量的限制。此外，繁殖者更有可能成为前一年繁殖成功率和密度相对较低的斑块中的迁入者，这表明定居受到多种线索的影响，这些线索可能揭示栖息地不同方面的信息，并在不同时刻可得。总体而言，我们的结果支持了社会线索对蓝山雀定居的重要性。
