Wire Marking Results in a Small but Significant Reduction in Avian Mortality at Power Lines: A BACI Designed Study

10 paginas, 4 figuras y 4 tablesBackground: Collision with electric power lines is a conservation problem for many bird species. Although the implementation of flight diverters is rapidly increasing, few well-designed studies supporting the effectiveness of this costly conservation measure have been published. Methodology/Principal Findings: We provide information on the largest worldwide marking experiment to date, including carcass searches at 35 (15 experimental, 20 control) power lines totalling 72.5 km, at both transmission (220 kV) and distribution (15 kV-45 kV) lines. We found carcasses of 45 species, 19 of conservation concern. Numbers of carcasses found were corrected to account for carcass losses due to removal by scavengers or being overlooked by researchers, resulting in an estimated collision rate of 8.2 collisions per km per month. We observed a small (9.6%) but significant decrease in the number of casualties after line marking compared to before line marking in experimental lines. This was not observed in control lines. We found no influence of either marker size (large vs. small spirals, sample of distribution lines only) or power line type (transmission vs. distribution, sample of large spirals only) on the collision rate when we analyzed all species together. However, great bustard mortality was slightly lower when lines were marked with large spirals and in transmission lines after marking. Conclusions: Our results confirm the overall effectiveness of wire marking as a way to reduce, but not eliminate, bird collisions with power lines. If raw field data are not corrected by carcass losses due to scavengers and missed observations, findings may be biased. The high cost of this conservation measure suggests a need for more studies to improve its application, including wire marking with non-visual devices. Our findings suggest that different species may respond differently to marking, implying that species-specific patterns should be explored, at least for species of conservation concern.We thank A. Garcıa Fernandez and M. Carrasco for their assistance during the field work. We also thank J. Camaño and J. Velasco of HENARSA, and the electric companies Iberdrola, Union Fenosa and Red Electrica de España for their cooperation. S. Young reviewed the English. RB was contracted within the project CGL2008-02567 of the Direccion General de Investigacion, Spanish Ministry of Science and Innovation and later supported by a postdoctoral grant from Junta de Comunidades de Castilla-La Mancha. C. Ponce, C. Palacın, CM and BM were supported by contracts CSICHENARSA. This study was carried out within the Preventive, corrective and compensatory measures to balance the impact of the M-50 and R-2 highways on the population of great bustards and other steppe-land birds in the Important Bird Area Talamanca-Camarma and the Site of Community Importance Cuenca de los rıos Jarama y Henares, supported by a contract HENARSA-CSIC. Additional financial support was provided by project GL2008-02567 of the Direccion General de Investigacion, Spanish Ministry of Science and Innovation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewe

Private lives, public identities: The Italians of Reading and Berks County, Pennsylvania, 1890-1940

This dissertation examines the process of immigration, community, and ethnic identity formation of Italians. It documents the meaning people attach to ethnic identity, how it evolves over time, and analyzes the flow between public and private domains by weaving gender throughout the discussion. Whereas the majority of ethnicity studies in the United States have focused on urban areas, this study looks at an ethnic population in a mid-size industrial town situated in a rural agricultural region. Adaptation was place specific. The new immigrants changed the social and political isolation of Reading and the city and region influenced the texture of the Italian community that evolved. Personal narratives and material culture data provide insight into understanding inside systems of knowledge and belief, in other words, how people construct their own history. This emic or folk view as well as symbols (both visual and verbal) encoded in the interrelated spheres of public and private life, provide key indications of intergroup and intragroup relations and cultural boundary creation, maintenance, and change over time. Differences (using the structural categories of gender, class, age, and generation) are revealed in ethnic experience by studying individuals in terms of their life histories and placing those histories in a broader framework of regional, national, and global economic-historical change. This approach reinforces the idea that ethnicity is an ideological strategy that changes over time and involves individual choice. The discussion moves from village life in Italy to settlement and family life in Reading, to the larger spheres of neighborhood and work, to organizational and institutional networks, and finally to the sphere of pageantry and ceremony. By transforming their self-identity as immigrants to Italian Americans, the generations created a unique past in Berks County. Italians created and shaped a collective history distinct from the mainstream cultural consensus through public ritual events--events of pageantry, ceremony and celebration. Over time, a popular ethnic memory emerged achieved through symbolic language, imagery, and enactment with which the diverse Italian population could identify

Private lives, public identities: The Italians of Reading and Berks County, Pennsylvania, 1890-1940

This dissertation examines the process of immigration, community, and ethnic identity formation of Italians. It documents the meaning people attach to ethnic identity, how it evolves over time, and analyzes the flow between public and private domains by weaving gender throughout the discussion. Whereas the majority of ethnicity studies in the United States have focused on urban areas, this study looks at an ethnic population in a mid-size industrial town situated in a rural agricultural region. Adaptation was place specific. The new immigrants changed the social and political isolation of Reading and the city and region influenced the texture of the Italian community that evolved. Personal narratives and material culture data provide insight into understanding inside systems of knowledge and belief, in other words, how people construct their own history. This emic or folk view as well as symbols (both visual and verbal) encoded in the interrelated spheres of public and private life, provide key indications of intergroup and intragroup relations and cultural boundary creation, maintenance, and change over time. Differences (using the structural categories of gender, class, age, and generation) are revealed in ethnic experience by studying individuals in terms of their life histories and placing those histories in a broader framework of regional, national, and global economic-historical change. This approach reinforces the idea that ethnicity is an ideological strategy that changes over time and involves individual choice. The discussion moves from village life in Italy to settlement and family life in Reading, to the larger spheres of neighborhood and work, to organizational and institutional networks, and finally to the sphere of pageantry and ceremony. By transforming their self-identity as immigrants to Italian Americans, the generations created a unique past in Berks County. Italians created and shaped a collective history distinct from the mainstream cultural consensus through public ritual events--events of pageantry, ceremony and celebration. Over time, a popular ethnic memory emerged achieved through symbolic language, imagery, and enactment with which the diverse Italian population could identify

Bird collision with power lines: estimating carcass persistence and detection associated with ground search surveys

International audienceThe quantification of bird mortality due to collision with power lines is complicated by the heterogeneity of survey methods used and the bias related to searching for carcasses on the ground (e.g., carcass persistence and imperfect detection by observers). To estimate the bias associated with ground search surveys, we conducted three 30-d trials to test carcass persistence by placing and monitoring carcasses of red-legged partridges (Alectoris rufa) and common pheasants (Phasianus colchicus) below power lines at 14 sites. We also conducted two detection experiments, testing the ability of 19 observers to detect bird carcasses. We used survival analysis and generalized linear mixed-effects models to investigate the effects of site, habitat, carcass size, and survey period on both carcass persistence and detection. We also investigated the effect of carcass age on carcass persistence and the effect of the observer on carcass detection. Our findings show significant variations in carcass persistence between sites and survey periods, as well as significant interaction between these variables. The daily carcass persistence probability was highly variable between sites, with an up to eightfold variation. Carcass detection increased with increasing carcass size and was significantly affected by the microhabitat surrounding the carcass; it also varied between observers. These findings suggest that both carcass persistence and detection vary strongly and unpredictably at a small scale. As a result, conservation managers should be encouraged to conduct carcass persistence and detection experiments on sites where they aim to produce unbiased estimates of bird mortality below power lines, and these trials should be carried out in conditions similar to the mortality survey. A large-scale, unbiased, and accurate estimate of bird collision mortality due to power lines may require substantial field effort, with a survey frequency of more than once a week