Drivers of power line use by white storks: A case study of birds nesting on anthropogenic structures

Anthropogenic structures are mainly known to have negative impacts on wildlife populations but they can be beneficial. Power lines are a main driver of bird mortality through collision or electrocution, but electricity pylons are also commonly used for nest building by some species. Birds and nests cause power outages that need to be tackled by electricity companies. However, the use of pylons by threatened species provides an opportunity for conservation purposes. In this study, we describe an empirical modelling approach to predict the circumstances under which nesting birds use electricity pylons. We focused on white storks Ciconia ciconia, a species that has been increasingly using electricity pylons for nesting across Europe. In a country‐level census in Portugal, we found a total of 1,348 white stork nests in 668 of the 8,680 very high‐tension power line pylons occurring in the distribution range of this colonial species, with spatial clustering in pylon occupation up to a distance of 30 km. The number of nests in each used pylon ranged from 1 to 21 (M ± SD = 2.2 ± 2.06). The main drivers of pylon use by nesting storks were distance to major feeding areas (rice fields, landfills and large wetlands), with more intensive use closer to these features, followed by land cover type surrounding each pylon. Pylon type and age, and stork population density in the region, had comparatively less importance. Synthesis and applications. We developed an approach to predict the use of anthropogenic structures by nesting birds that can be used both for species conservation and minimising damage to infrastructures. For power lines, applications include: (1) planning power line routes to take account of the probability of pylon use; (2) applying nesting deterrent devices (to reduce bird mortality and power outage risk) and providing nesting platforms (to promote bird use) on suitable pylons and (3) selecting adequate pylon types to promote or inhibit nesting.