Raptor mortality by electrocution in power lines in eastern Sierra Morena and Campo de Montiel (Spain).

Published:

Volume 45(2), December 1998. Pages 161-169.

Language:

Spanish

Original title:

Electrocución de rapaces en líneas eléctricas de distribución en Sierra Morena Oriental y Campo de Montiel.

Keywords:

Aquila adalberti, Aquila chrysaetos, electrocution, Hieraaetus fasciatus, mortality, power lines, raptors, Sierra Morena, Spain.

Abstract:

A survey of bird (mainly raptor) electrocutions at ten power lines in Campo de Montiel and eastern Sierra Morena is reported. During 1988-1996, 274 dead raptors of 14 species (Fig. 2) were found along 69 km of distribution power lines, with a total of 1629 pylons surveyed. Electrocution mortality was specially important for large raptors (14 corpses of Spanish Imperial Eagles Aquila adalberti, 23 of Golden Eagles Aquila chrysaetos and 17 of Bonelli's Eagles Hieraaetus fasciatus were found). Pylon design and the type of vegetation around pylons showed significant effects on mortality indices. Anchoring pylons and rigid insulator pylons (Fig. 1) caused 99.6% of the observed electrocutions. Frequencies of electrocution were significantly higher at power lines close to Sierra Morena, in areas where shrubland predominates. This result could be partially explained by larger prey (mainly rabbits Oryctolagus cuniculus) density in shrublands, and indirectly by a higher density of raptors in this habitat. A negative significant correlation was found between mortality and distance to the nearest Aquila adalberti nest. This distance also indicated the distance from power lines to Sierra Morena, which is the main breeding area for most of the raptor species found electrocuted. Priorities in order to modify or replace power lines should consider the pylon design, type of vegetation and distance from power lines to breeding areas.