Brown CR, Brown MB
Department of Biological Sciences, University of Tulsa
Anim Behav. 2000 Jan;59(1):47-55. doi: 10.1006/anbe.1999.1277.
How colonial animals space their nests in relation to conspecifics may provide clues as to whether coloniality provides net benefits or occurs only because breeding sites are limited. We examined how nearest-neighbour distance varied in relation to settlement time in the highly colonial cliff swallow, Petrochelidon pyrrhonota, comparing observed nearest-neighbour distances to those expected if birds spread out to maximize nest spacing. Cliff swallows generally settled closer to each other than required by the available substrate, and clustered their nests closer in large colonies than in small ones. The first settlers at a colony site spaced themselves further apart than later arrivals but did not maximize nearest-neighbour distances. The first arrivals maintained greater nest spacing throughout the season than did birds that arrived later. Colony size and amount of nesting substrate had no effect on initial settlement distances of the first arrivals, but eventual nearest-neighbour distances declined with colony size. First arrivals may gain less from nesting with conspecifics and thus are less likely to cluster their nests than later arrivals, which may often be young or naïve birds that gain more from the social benefits of colonial nesting. The results are consistent with the presumed social advantages cliff swallows receive from coloniality and do not support the hypothesis that colonies result from nesting site limitation. Copyright 2000 The Association for the Study of Animal Behaviour.
群居动物如何根据同种个体来确定其巢穴间距，这或许能为群居行为是否带来净收益，或者仅仅是因为繁殖地点有限才出现提供线索。我们研究了高度群居的崖燕（学名：Petrochelidon pyrrhonota）中，最近邻距离如何随定居时间而变化，将观察到的最近邻距离与假设鸟类为使巢穴间距最大化而散开时预期的距离进行比较。崖燕通常彼此靠得比可用筑巢基质所要求的更近，并且在大群体中比在小群体中巢穴聚集得更紧密。一个群体地点的首批定居者彼此间隔比后来者更远，但并未使最近邻距离最大化。整个季节中，首批到达者保持的巢穴间距比后来到达的鸟类更大。群体大小和筑巢基质数量对首批到达者的初始定居距离没有影响，但最终的最近邻距离随群体大小而减小。首批到达者与同种个体一起筑巢可能获得的收益较少，因此比起后来者，它们不太可能使巢穴聚集在一起，后来者往往可能是年轻或缺乏经验的鸟类，它们从群居筑巢的社会益处中获得更多。这些结果与崖燕从群居行为中获得的假定社会优势相一致，并不支持群体是由筑巢地点限制导致的这一假设。版权所有2000动物行为研究协会。
