Collision of birds against the ground wire and conductors of high tension lines can be a serious neotropics problem in some habitats and for some bird species. Data on collision were gathered in a wetland locality crossed by a 2 circuit 500 kV line in northern Colombia. After 2 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 proved to reduce mortality of birds as shown by fewer