Gilroy James J
School of Environmental Sciences, University of East Anglia, Norwich, UK.
J Anim Ecol. 2017 Sep;86(5):983-986. doi: 10.1111/1365-2656.12717.
In Focus: Lok, T., Veldhoen, L., Overdijk, O., Tinbergen, J. M., & Piersma, T. (2017). An age-dependent fitness cost of migration? Old trans-Saharan migrating spoonbills breed later than those staying in Europe, and late breeders have lower recruitment. Journal of Animal Ecology, 86, 998-1009. In Focus: Grist, H., Daunt, F., Wanless, S., Burthe, S. J., Newell, M. A., Harris, M. P., & Reid, J. M. (2017). Reproductive performance of resident and migrant males, females and pairs in a partially migratory bird. Journal of Animal Ecology, 86, 1010-1021. In this issue, two studies examine the extent to which variation in migratory behaviour influences individual fitness across a population. Lok, Veldhoen, Overdijk, Tinbergen, and Piersma () examine reproductive success and post-fledging survival in a population of Eurasian spoonbills (Platalea leucorodia), comparing individuals that winter in south-west Europe against those migrating to sub-Saharan Africa, while Grist et al. () measure reproductive success in a population of European shags (Phalacrocorax aristotelis) breeding in Scotland that either remain resident or migrate to surrounding waters. Both studies find that individuals migrating longer distances tend to show later initiation of breeding attempts. In turn, longer migration correlates with lower reproductive success in both populations. In spoonbills, this effect is most pronounced in older male birds, while young individuals show little difference in breeding success with respect to migration distance. In shags, fitness benefits of residence were most pronounced when both individuals of a pair were resident, although there was no evidence of assortative mating. Both studies provide fascinating new insights into the role migratory variability can play in shaping population dynamics.
洛克，T.，费尔德霍恩，L.，奥弗迪克，O.，廷贝亨，J. M.，& 皮尔斯马，T.（2017年）。迁徙存在与年龄相关的适合度成本？跨撒哈拉迁徙的白琵鹭繁殖时间比留在欧洲的白琵鹭晚，且繁殖晚的个体后代补充率较低。《动物生态学杂志》，86卷，998 - 1009页。焦点文章：格里斯特，H.，当特，F.，万利斯，S.，伯特，S. J.，纽厄尔，M. A.，哈里斯，M. P.，& 里德，J. M.（2017年）。部分迁徙鸟类中留居和迁徙的雄性、雌性及配对个体的繁殖表现。《动物生态学杂志》，86卷，1010 - 1021页。在本期中，两项研究探讨了迁徙行为的差异在多大程度上影响一个种群中个体的适合度。洛克、费尔德霍恩、奥弗迪克、廷贝亨和皮尔斯马（）研究了欧亚白琵鹭（白琵鹭）种群的繁殖成功率和出飞后存活率，比较了在欧洲西南部越冬的个体与迁徙至撒哈拉以南非洲的个体，而格里斯特等人（）测量了在苏格兰繁殖的欧洲鸬鹚（普通鸬鹚）种群的繁殖成功率，这些鸬鹚要么留居原地，要么迁徙至周边水域。两项研究均发现，迁徙距离更远的个体往往繁殖尝试开始得更晚。相应地，在这两个种群中，更长的迁徙距离都与较低的繁殖成功率相关。在白琵鹭中，这种影响在老年雄鸟中最为明显，而年轻个体的繁殖成功率在迁徙距离方面差异不大。在鸬鹚中，当配对的双方都留居时，留居的适合度优势最为明显，不过没有证据表明存在 assortative mating。两项研究都为迁徙变异性在塑造种群动态中可能发挥的作用提供了引人入胜的新见解。
