Vulnerable birds to collide against wind towers in Rivas, Nicaragua, before construction

Abstract

A Bird Vulnerability Index (BVI) and Potential Vulnerability Map (PVM) was applied to determine which are the most susceptible bird species to collide with wind towers and the riskiest sites, in a wind power plant south from the city of Rivas. Transects were placed in two areas where the towers would be placed: Grasslands without Trees and Grasslands with Trees. Transects were also made in adjacent habitats such as Lake Nicaragua Coast and Riparian Forest. The BVI was calculated with nine factors (Flight Height, Type of Flight, Wingspan, Weight, Status, Abundance, Reproductive Status, International and National Conservation Status). The total PVM was calculated from all detected species, and average PMV only using species that exceeded the specific BVI median. The risk of habitat collision was calculated by determining that less of 50th percentile is considered to be low risk, and high risk when the percentile is greater than 50. The highest vulnerability index is found in the species: Magnificent Frigatebird (Fregata magnificens), Black Vulture (Coragyps atratus), Turkey Vulture (Cathartes aura), Osprey (Pandion haliaetus), Crested Caracara (Caracara cheriway), Nicaraguan Grackle (Quiscalus nicaraguensis), and Great Heron (Ardea herodias). The riparian forest and grassland with trees are the sites with the highest risk of collision to install wind towers. The BVI and PVM are important tools that allow the identification of potential risks of bird collision with wind towers before their construction.