Effects of Nest Box Installation on a Distribution Power Line: Increased Eurasian Kestrel Nesting, Reduced Electrocutions, and Reduced Electrical Faults

Abstract

Electrical pylons are frequently used by birds for perching, roosting, and nesting. These behaviors can lead to electrocutions, particularly when pylons are constructed of grounded concrete and steel crossarms, as they were in our study area near Arak, Iran. To address electrocutions of Eurasian Kestrels (Falco tinnunculus) and a variety of passerines nesting on a 20-kV distribution line, we documented construction and use of nests on pylons on a 34-km segment of power line in 2018. Following removal of nests by the electric utility operating the line, we installed nest boxes on pylons that previously supported nests, and in 2019 we documented use of those nest boxes. We predicted that after installation of nest boxes, numbers of Eurasian Kestrel nests would increase, and numbers of nests outside of nest boxes, avian electrocutions, and faults (electric current arcing from conductors to pylons) would decrease. All four predictions were validated. We documented 31 nests in 2018, including 3 Eurasian Kestrel nests. In 2019, we documented 6 nests outside of nest boxes, and 31 nests in nest boxes, including 16 Eurasian Kestrel nests. In 2018, we found 1 electrocuted Eurasian Kestrel, and 39 electrocuted passerines. In 2019, we found 3 electrocuted Eurasian Kestrels, 11 passerines, 2 Eurasian Eagle-Owls (Bubo bubo), and 1 Steppe Eagle (Aquila nipalensis). The rate of electrocutions per nest for Eurasian Kestrels decreased from 0.33 to 0.19, and the electrocution count for all birds decreased by 57.5%. Electrical faults, an indirect measure of potential avian electrocutions, decreased from 173 in 2018 to 120 in 2019. Although there is some risk that nest boxes on power poles could create ecological traps, our results suggest that in this study electrocutions and electrical faults were reduced, supporting conservation goals and electric power reliability goals while simultaneously reducing electric utilities' maintenance obligations.

Crowd‐sourced reporting of birds nesting on power lines in Iran

“…The occurrence of birds nesting on electric infrastructure is well‐known globally (Ferrer 2012, Dwyer and Dalla Rosa 2015, Moreira et al 2018, Kolnegari et al 2020 a ) but the extent of nesting is not as well understood, partly because ornithologists are unable to visit all of the considerable electrical infrastructure that exists worldwide. We used crowd‐sourced data from electric utility linemen to broaden our knowledge of birds nesting on power lines in Iran.…”

“…In the absence of intervention, Eurasian magpies will presumably continue to nest on 63‐kV structures. These nests generally will not create safety or reliability concerns for electric utilities, but if Eurasian magpies create conservation concerns for other species, as corvids sometimes do elsewhere (Jerzak 2001, Marzluff and Neatherlin 2006), then approaches such as installing nest boxes to leverage interspecific competition may be directed to 63‐kV structures (Kolnegari et al 2020 a ). We also found that 20‐kV structures supported proportionally large numbers of Eurasian magpies.…”

“…We also found that 20‐kV structures supported proportionally large numbers of Eurasian magpies. Nest boxes can reduce Eurasian magpie numbers on 20‐kV structures in Iran, but electrocution risks will persist (Kolnegari et al 2020 a ). Addressing avian electrocution concerns in those situations requires the application of isolation (increasing separation between pieces of energized equipment), insulation (covering energized equipment), or redirection (installing perch deterrents or nest boxes) to limit risks of electrocutions, equipment damage, fires, and power outages (Dwyer et al 2017).…”

“…When posted information was unclear, we contacted the lineman who made the post, and requested details. We included all nests reported except those that were part of a concurrent study we conducted evaluating the effects of installing >80 nest boxes on power lines in Iran (Kolnegari et al 2020 a ). We used observation dates and comparison of images collected on the same dates to ensure that we did not accidentally create duplicate records of the same nests from multiple sources.…”

“…For example, Kolnegari and Harness (2020) evaluated the roles that various electrical components play in avian electrocutions and power outages. Kolnegari et al (2020 a ) quantified effects of nest box installation on decreasing avian electrocutions and power outages. Kolnegari et al (2020 b ) documented the avifauna species associated with power outages, and Kolnegari et al (2020 c ) studied the effects of line markers installed on power lines to reduce avian collisions.…”