Power Lines, an Understudied Cause of Avian Mortality in Mexico

Background and Research Aims Power lines are one of the main anthropogenic causes of bird mortality on a global scale, but research is scarce in some countries with a high diversity of birds, such as Mexico. In this study, we assessed the impact of bird collisions and electrocutions with power lines on avian communities at three wind farms located in three different states in Mexico. Methods Carcass searches were carried out at sites in Tamaulipas (4 months in 2021), Guanajuato (2 months in 2020, 4 months in 2021), and Oaxaca (55 months from 2014 to 2021). Results A total of 579 bird carcasses from 65 different species were recorded. The White-winged Dove (Zenaida asiatica) was the most frequently found species (282 records) across the three sites. When considering the number of species identified per family, Icteridae had the highest number of species at the Oaxaca site, Columbidae and Passerelidae at the Tamaulipas site, and Anatidae at the Guanajuato site. At the order level, Passeriformes had the highest number of species at the Tamaulipas and Oaxaca sites, and Anseriformes in Guanajuato. Of the total species recorded, 12 are within some category of risk according to Mexican legislation and the IUCN Red List, and 18 are migratory species. Conclusions Our results, together with evidence from previous studies, indicate that power lines represent one of the main causes of anthropogenic mortality in Mexico in terms of the number of affected bird species. Further research is urgently needed to explore the effect of power lines on bird populations in the country, particularly those at risk of extinction, and migratory species. Implications for Conservation The high diversity of species found to be affected in this study highlights the wide-ranging impact of these structures and the need to implement mitigation strategies at the three sites studied, particularly for the most affected species, the White-winged Dove (Zenaida asiatica).