Migratory birds generally have higher dispersal propensity than resident species and are thus expected to show less genetic differentiation. On the other hand, specific migration patterns may promote genetic structure, such as in situations where migratory divides impede random mixing of individuals. Here we investigated population genetic structure and gene flow patterns in a polytypic passerine, the reed warbler Acrocephalus scirpaceus which shows a migratory divide in central Europe. Using ten polymorphic microsatellite loci and extensive sampling we found low but significant overall genetic differentiation (F ST 00.013, G' ST 00.078, D 00.063). Hierarchical F-statistics and barrier analyses showed low but significant genetic differentiation of Iberian populations, and also slight genetic differences across the migratory divide and between subspecies ( A. s. scirpaceus and A. s. fuscus). Three individual-based Bayesian methods, however, inferred a single genetic unit. Our study thus found low levels of genetic differentiation among reed warbler populations but this genetic differentiation was not pronounced enough to detect a clear population structure using the microsatellite data and no prior information on geographic location of the sampled individuals. This result indicates high levels of gene flow and suggests a possibly recent divergence of European populations after a rapid range expansion. Further studies are necessary to assess divergence times and to reveal the evolutionary history of the reed warbler populations.

Community‐level studies have shown that plant–pollinator interactions are much more generalized than previously expected. Consequently, many authors have questioned the significance of phenotypic complementarity between plants and pollinators and abundance effects in pollination interactions. Here, we compare the behaviour of three sunbird species feeding on the nectar of five plant species in afromontane vegetation. We studied the feeding behaviour with and without consideration of plant abundance (i.e. diet selectivity and diet composition, respectively). The aims of the study were to estimate: (1) how relative resource abundance influences flower selectivity; (2) the degree of phenotypic matching; and (3) whether different plant resource assessment methods give different answers to this question. The results showed that, although sunbirds frequently feed on both morphologically adapted and nonadapted plants, food selectivity data are consistent with the hypothesis of phenotypic complementarity. Moreover, we found that the type of plant abundance measurement can change conclusions in some cases, as individual plants differ in their growth habits and nectar production. This effect was most obvious for the assessment of selectivity of the northern double‐collared sunbird (Cinnyris reichenowi) and for Hypoestes aristata, a plant producing inflorescences composed of a large number of small flowers possessing small amounts of nectar per flower (a high abundance of flowers, but a low abundance of nectar relative to the remaining plant community). © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••–••.

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We tested the genetic and ecological differences between neighbouring urban and rural populations of common kestrels (Falco tinnuculus) in southern Bohemia. The aims were to (1) assess the genetic variability of the studied kestrel populations using microsatellite markers, (2) check the genetic relatedness of individuals within the urbanization gradient, and (3) compare possible gradients of body characteristics and reproductive parameters on the urbanization gradient. The mean expected allelic polymorphism did not differ among the studied populations, which were not genetically separated (F ST = 0.0003, P = 0.781). Also, an individual assignment test did not show a separation of these populations. Urban kestrels that bred in the city centre were indicatively more related than others, and no relationship was found in the rural kestrel population. Kestrel females were heavier towards the city centre, but males did not show this relationship. Nest distance from the city centre had no significant effect on any of the tested reproductive parameters. Our results do not support the notion of genetic differentiation between rural and urban kestrels, but revealed trends in body characteristics and genetic relatedness along the urbanization gradient.