DOI: 10.5061/dryad.p5hqbzkwp
title: Tasmanian wedge-tailed eagle power line crossings

description: Avian fatalities caused by collisions with overhead power lines are an
 important conservation issue worldwide. Although mitigation strategies can
 help reduce mortalities, given their considerable cost and the vast scale
 of power line infrastructure, cost-effective action requires that these
 efforts be prioritised to areas with the highest potential risk to birds.
 To date, this risk assessment has usually been guided by potentially
 biased information on the location of recorded fatalities. Here we use six
 years of GPS tracking data from endangered Tasmanian wedge-tailed eagles
 to develop an alternative approach to risk assessment: fine-scale spatial
 risk models based on behavioural analyses. We built and cross-validated a
 model that generates spatially explicit predictions of the probability
 that eagles would cross power lines at hazardous altitudes throughout the
 entire Tasmanian electricity distribution network. In our model,
 probability of power line crossings was most strongly associated with the
 proportion of open habitat, forest edges, rural residential developments,
 wet forest, and freshwater sources in the area surrounding the power
 lines. Cross-validation indicated that the model effectively predicted
 where Tasmanian wedge-tailed eagles cross power lines at low altitude.
 Model validation suggested our approach was a powerful predictor of the
 locations of power line collisions involving eagles. The locations of
 almost all (94%) confirmed eagle fatalities were in the half of the total
 Tasmanian power line area assigned the higher risk by the model, and 50%
 of incidents occurred in the 20% of the power line area estimated to be
 highest risk. Synthesis and applications. Our study illustrates a
 framework for using bird movement data to provide insights into avian
 behaviour and the risk they encounter around power line infrastructure.
 Electricity delivery industries can use these models to identify the
 electrical infrastructure that poses the highest risk to avian survival
 and prioritise mitigation efforts, thereby optimizing the benefit of
 investments to reduce detrimental effects on biodiversity. Our model can
 inform pre-emptive mitigation across Tasmania’s 20,310 km of distribution
 infrastructure to meet management targets aiming to reduce the negative
 effects of power lines on the Tasmanian wedge-tailed eagle.
description: This data set is of locations where 23 young Tasmanian
 wedge-tailed eagles crossed power line infrastructure at low altitude
 between 2017 and 2023.  It includes a unique identifier
 for each eagle ('name'). The variables include the sex of the
 bird ('sex'), the age class of the bird ('ageclass'),
 the season, the month, the number of months since fledging
 ('monthsincefledge'), and the time of day of the crossing
 ('timeofday'). The unscaled values for each of 13 landscape
 variables (agricultural area, distance to nearest ridge, dry forest area,
 elevation, forest area, forest edge, open area, residential buildings,
 ruggedness, rural residential area, slope, urban area, water area, wet
 forest area) measured for the crossings, including a suffix designating
 the spatial scale of the measurement, are also included. 
description: # Tasmanian wedge-tailed eagle power line crossings
 [https://doi.org/10.5061/dryad.p5hqbzkwp](https://doi.org/10.5061/dryad.p5hqbzkwp) ## Description of the data and file structure ### Files and variables #### File: TWTEcrossingdata\_v4.csv * name: unique eagle identifier  - sex: sex of the eagle as determined from genetic sample - ageclass: age class separated into different categories (PFDP = post-fledging dependence period; firstyrdisp = first year of dispersal; secondyrdisp = second year of dispersal; thirdyrdisp = third year of dispersal...) - season: season of observation - month: month of observation - monthsincefledge: number of months since the eagle fledged the nest - timeofday: time of day that the crossing occurred  - openarea349: proportion of open habitats  - forestedge815: proportion of forest edges - residentialarea30: proportion of rural residential area - agriculturalarea349: proportion of agricultural area - waterarea349: proportion of water area - wetforestarea349: proportion of wet forest area - distancetoridge30: distance to nearest ridgeline (meters) - dryforestarea349: proportion of dry forest area - residentialbuildings30: number of residential buildings - ruggedness815: ruggedness of the terrain (derived from a 25 m Digital Elevation Model - the 3-dimensional surface area of each cell [calculated from surrounding eight cells] divided by the flat area of the cell) - slope2297: slope of the terrain in degrees (derived from a 25 m Digital Elevation Model) - elevation349: elevation (m above sea level) - urbanarea1126: proportion of urban area