2003

Collision of birds against the ground wire and conductors of high tension lines can be a serious problem in some habitats and for some bird species. Data on collisions were gathered in a wetland locality crossed by a 2 circuit 500kV line in northern Colombia. After two years of study mitigation devices (yellow plastic spirals) were installed on one circuit and observations were carried on after the installation in order to evaluate the effectiveness of the spirals. The bird flight diverters (BFD) proved to reduce mortality of birds as shown by fewer birds reacting close to the line, fewer birds flying at the height of the conductors and lower collision rates with the marked line. This pioneer study in the region provides an appropiate methodology for the study of the effects of transmission lines on birds in the Neotropics. We conclude that collision might have serious effects in the country and might be critical for some local populations, especially crepuscular, medium to large-sized species with limited flight maneuverability. A number of preventive recommendations for electric companies are given. An important recommendation is to install BFD in all portions of transmission lines in critical areas. This practice is being implemented throughout the country.