Suchergebnisse

AbstractHuman's activities dominates many aspects of the Earth's environment; thus animals are forced to adapt and respond to the resulting changes in habitat structure and functioning due to anthropogenic pressure. Along with the growing human population and the associated amount of waste produced, the amount of different type of physical contamination component in environment is increasing. Incorporation of debris in nests may be a mounting avian response to anthropogenic pollution. In this research, we quantified the constituent pieces and total mass of human-derived materials incorporated in white stork nests. The study was conducted on four locations in central Spain where white storks nest along a urbanization gradient. In total, we examined 49 nests. This study demonstrates that the incorporation of debris by white storks into their nests is related to human activity, measured by the Human Footprint Index (HFI). Moreover, the distance between these nests and landfills predicts the occurrence of debris incorporated into nests. Our study shows that birds nest building behaviour is impacted by human activities and pollution in environment.

Leucism is the total or partial lack of melanins in the skin and associate structures (i.e. hair or feathers). Little is known about the factors influencing this chromatic aberration although some local studies suggest that there is an effect of habitat, age and sex. To test these hypotheses and expand our knowledge on leucism, we carried out a large-scale study using common blackbirds Turdus merula as our model species. Given the poor information available on this topic and the variability of methodological approaches, we used three different methods to assess the effect of these variables in the presence of leucism: transects, bird captures and citizen science information (pictures from internet). We found an effect of habitat indicating that there are more leucistic blackbirds in cities than in non-urban areas. In addition, we found a positive association between presence of white feathers and age providing the first large-scale support for the progressive graying hypothesis in birds. This chromatic aberration was also influenced by sex, with males showing higher probability of leucism than females, although only for the capture data, indicating that the method used to study this phenomenon can partly influence our conclusions, and therefore suggesting caution when planning future studies in this topic. ; JDI was funded by a postdoctoral contract (TAHUB- 104) from the program 'Andalucía Talent Hub' (co-funded by the European's Union Seventh Framework Program Marie Skłodowska- Curie actions – COFUND – and the regional Government of Andalucía). ADF was funded by a Severo Ochoa grant (SVP-2014- 068571) from MICINN (Spain).

AbstractA major impact of human development is the transformation of natural habitats into farming lands and the expansion of built-up areas. Also, plastic pollution is affecting wildlife on a global scale. Discarded plastic is ubiquitous and accessible for birds, which can incorporate them into the nest structure. Here, we describe the differences in type, prevalence, and the amount of anthropogenic nest materials between two populations of terrestrial, mainly farmland bird, the white stork Ciconia ciconia, on a broad geographical scale, from two migratory divides—eastern in Poland and western in Spain (in total 303 nests). In the two populations, we detected significant differences in the incorporation of anthropogenic nest material, as measured by the Human Footprint Index (HFI) and the Impervious Surface Areas (ISA). We found that ISA was positively related to anthropogenic nest material incorporation in the Spanish population, and HFI was positively related to anthropogenic nest material, in contrast to the Polish population, in which the relationships were not significant. Moreover, we showed that the prevalence of nests with anthropogenic nest material was two times higher in Spanish than in the Polish white stork population. This study demonstrates that the behavior of incorporation of the anthropogenic nest material differs between two distinct populations of a single bird species.

Urbanization changes the landscape structure and ecological processes of natural habitats. While urban areas expose animal communities to novel challenges, they may also provide more stable environments in which environmental fluctuations are buffered. Species´ ecology and physiology may determine their capacity to cope with the city life. However, the physiological mechanisms underlying organismal responses to urbanization, and whether different physiological systems are equally affected by urban environments remain poorly understood. This severely limits our capacity to predict the impact of anthropogenic habitats on wild populations. In this study, we measured indicators of physiological stress at the endocrine, immune and cellular level (feather corticosterone levels, heterophil to lymphocyte ratio, and heat-shock proteins) in urban and non-urban European blackbirds (Turdus merula) across 10 European populations. Among the three variables, we found consistent differences in feather corticosterone, which was higher in non-urban habitats. This effect seems to be dependent on sex, being greater in males. In contrast, we found no significant differences between urban and non-urban habitats in the two other physiological indicators. The discrepancy between these different measurements of physiological stress highlights the importance of including multiple physiological variables to understand the impact of urbanization on species' physiology. Overall, our findings suggest that adult European blackbirds living in urban and non-urban habitats do not differ in terms of physiological stress at an organismal level. Furthermore, we found large differences among populations on the strength and direction of the urbanization effect, which illustrates the relevance of spatial replication when investigating urban-induced physiological responses. ; JDI was funded by a postdoctoral contract (TAHUB-104) from the program "Andalucía Talent Hub" (co-funded by the European's Union Seventh Framework Program Marie Skłodowska-Curie actions -COFUND- and the regional Government of Andalucía). DG was funded by a research grant from the Spanish Ministerio de Ciencia, Innovación y Universidades (CGL2014-55577-R). JF was funded by a research grant from the Spanish Ministerio de Economía y Competitividad (CGL2012-30759). ADF was supported by a Severo-Ochoa grant from the Spanish Ministerio de Economía y Competitividad (SVP-2014-068571). ; Peer reviewed