Wedgie risk-assessment tool developed in Tasmania

Power strike

Wedgie risk-assessment tool developed in Tasmania

Wedge-tailed Eagles are widespread right across Australia. If you’re away from built-up areas on the mainland, it’s generally not too hard to spot one, at least occasionally. However, it’s a different story across Bass Strait, where the species is not nearly as common. Indeed, the Tasmanian subspecies of the Wedge-tailed Eagle is considered threatened, being officially classified as Endangered. It’s a situation which might surprise a few mainlanders.

The eagle’s threatened status is due mainly to widespread destruction of its wooded habitats. Renowned for its soaring flight, this is a contributing factor in the increasing incidence of the birds colliding with the many powerlines which criss-cross the state. In a similar vein, accidental electrocution from striking infrastructure associated with the power grid is also on the rise.

The eagle population in Tasmania is around 350 breeding pairs, and between 2017 and 2023, 110 Wedge-tailed Eagles were injured or killed by powerline infrastructure across Tasmania (though incidents are likely to be under-reported). The situation in Tasmania has reached the point where a significant proportion of eagles taken into care are there because of collisions with powerlines.

To address this emerging issue, TasNetworks, the local power provider, spends $1 million each year to mitigate avian collisions with its infrastructure, and has installed thousands of small reflective disks that hang from the powerlines — known in the industry as ‘flappers’ — along 600 kilometres of their wires (just under 3% of the network) to deter birdstrike. Though this undoubtedly prevents a few collisions, the incidence is still worryingly high in such a small population.

Against this background, experts from the University of Tasmania have developed a model that predicts where the Wedgies are most likely to encounter powerlines, and where the risk of death is greatest. For six years, they tracked the flights of 23 Wedge-tailed Eagles around different regions of Tasmania, and used the data gathered to inform their risk-assessment tool.

Using this predictive tool, TasNetworks will be able to target hotspots for installing collision-mitigating features.
This tool is one of a number of risk-assessment tools currently being used around the country to predict threats that Australia’s birds are likely to face. For instance, experts at BirdLife Australia have been at the forefront of the development of the new AviFlu Map to prepare Australia for an outbreak of the deadly H5 bird flu, using information gathered by our army of volunteer citizen scientists.