National Repository of Grey Literature 2 records found  Search took 0.00 seconds. 
Species-specific and individual predictors of birds' collisions with glass obstacles in the Czech Republic
Semeráková, Anna ; Sedláček, Ondřej (advisor) ; Viktora, Lukáš (referee)
Recent landscape transformation is associated with the emergence of various artificial obstacles that change the natural form of habitats and biocorridors of free-ranging animals. Glass obstacles represent a particular problem due to their transparency and reflectivity. Collisions with glass represent one of the most significant causes of bird mortality worldwide, accounting for over hundreds of millions bird deaths annually. Many authors consider this source of mortality to be completely non-selective. In that case, total collisions mortality would represent a function of population size. However, here I assume that the relationship between collision mortality and population size is more complex and that certain avian ecological groups may be differently susceptible to glass collisions based on their specific ecological characteristics. Long-term records of bird-glass collisions in the Czech Republic were provided by the Czech faunistic databases. These records were compared with the population size of analysed species and with selected ecological and morphological species characteristics. Consistently with the premise, I found out that the greatest amount of collision mortality is explained by the species' population size. However, other species characteristics, such as higher body weight,...
Ecological and ethological aspects of bird-building collisions
Semeráková, Anna ; Sedláček, Ondřej (advisor) ; Koleček, Jaroslav (referee)
Collisions with artificial structures represent one of the most significant cause of bird mortality worldwide. Accounting for hundreds of millions bird deaths each year, bird-building collisions represent a particular problem. Although the bird's vision system is perfectly adapted to the orientation during fast flight, birds are often confused due to the transparency or reflectivity of the glass. Moreover, light pollution of urban areas interferes with the physiological geomagnetic and polarized light compass in birds, which causes the night migrants to disorient. The bird-building collision frequency variates in time and space. Throughout the day, largest number of fatal collisions occurs during early morning. Throughout the year, the peak in the numbers of fatal strikes appears in the course of autumn migration. Local species abundance did not appear to be the most important predictor of collision probability. Species traits making birds highly prone to collisions are small body size, high flight speed, long distance of migration and feeding strategy requiring rare and temporary food sources. Aggressive males during the mating period and inexperienced post-fledging juveniles are among the most vulnerable individuals. Based on taxon-specific ecological traits, some bird families were identified to...

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