Birds coming in to contact with powerlines is faced by electricity distribution and transmission companies throughout Australia and overseas. Of particular concern are incidents involving threatened birds of prey. Each year, a small but significant number of Tasmanian Wedge-tailed eagles, Grey Goshawks and White-bellied sea eagles are killed as result of flying into live conductors or perching on power poles.
To explain how we’re working to address this issue, we’ve put together the below Q&A.
How are you working to protect threatened birds from the electricity network?
We're taking a proactive and strategic approach to managing this issue, operating under a five-year Threatened Birds Strategy (2016- 2021). The strategy aims to materially reduce the impact of the electricity network on Tasmania’s threatened birds of prey; specifically the Grey Goshawk, Tasmanian Wedge-tailed wagle and White-bellied sea eagle. It's based around three core components:
Building knowledge and awareness
Mitigating the risk
Voluntarily offsetting our impact through conservation activities
Prior to our Threatened Bird Strategy being developed, our predecessors invested a range of management actions. This included the establishment of a Public Authority Management Agreement with the Department of Primary Industries, Parks, Water and Environment (DPIPWE), stipulating we'll report all incidents relating to threatened birds, and will work collaboratively with DPIPWE’s Threatened Species Unit to manage our impact in a strategic manner. This agreement has been in place since 2008.
How are threatened birds of prey impacted by the electricity network?
There's little data how on threatened birds of prey behave around the electricity network. However, we investigate all known incidents and from this data we know two thirds of Wedge-tailed eagle fatalities occur when an eagle flies directly into powerlines. Because of their huge wing span – upwards of 2.3m for a female Tasmanian Wedge-tailed eagle – large birds of prey can touch two powerlines at the same time, and this is what creates the danger of electrocution. The remaining third of reported Wedge-tailed eagle fatalities are caused at the pole top, either by touching two conductors at once, or by contacting a conductor from an "earthed" position, for example while sitting on a crossarm.
What are you doing under the mitigation part of the strategy?
One of the ways we're working to protect threatened birds of prey from flying into powerlines is by making powerlines more visible. This is done by installing devices called bird diverters or "flappers".
Flappers are durable plastic disks, about 10cm in diameter, which attach to the powerlines and swivel in the wind. The flappers we use also contain glow-in-the-dark natural crystals, which absorb and emit purple ultraviolet light. This makes the flappers visible to the raptors during the day and night, but appear as white plastic to humans.
Due to their huge wing span, large raptors including Wedge-tailed eagles can also receive an electric shock while perching on a pole top. There are two things we can do to address this issue, depending on the specifics of the pole-top configuration. The first is to install an insulative covering, called ‘redback’, on the bare wires at the top of the power pole. This ensures that if a bird touches these parts of the infrastructure, there is a barrier to prevent electrocution.
The second is by installing bird perches. Perches keep birds away from the live parts of the pole-top crossarm by giving them a place to perch, which is higher than the rest of the infrastructure.
In the 2016-17 financial year, we installed bird mitigation at a number of sites across the state including at Ross, Claremont, Newstead, Bracknell, Richmond, Campania, Ouse, Brighton, Lebrina, Woodbury and Campbell Town.
In August 2017, we mitigated a site at Tunbridge Tier Road, near Ross in the Southern Midlands. This job included the installation of bird perches, insulation covers and bird flappers on approximately 4.5km of the network.
We'll continue to install mitigation on our infrastructure. Right now, we’re in the process of scheduling three jobs, which will see 34kms of powerline mitigated with flappers and 58 pole bird perches installed, at sites near Fingal in the north-east, as well as York Plains and Lower Marshes in the Southern Midlands.
How do you decide which areas of the electricity network to mitigate?
We have limited data to assist us in prioritising where to install mitigation. Our Design and Strategic Asset Management teams currently look to a range of academic literature, local expert opinion and previous incident data to identify priority locations.
A lack of scientific data to direct the placement of mitigation is one of the reasons we're investing in research to help us better understand if risk factors such as landscape characterises and active nest sites, are associated with threatened birds of prey coming into contact with our network.
We’ve recently engaged a contractor to help us develop a risk map, with the aim of identifying priority areas for mitigation. This complex project will take a number of months to complete, however, we’re confident once it’s in it will be an effective tool in prioritising future mitigation work. We’ll keep you updated on how we progress with this work, as it’s an exciting development that could have a big impact for threatened birds of prey.
What are you doing to build knowledge and awareness?
We've provided funding support to University of Tasmania PhD candidate James Pay, who is looking into the behavioural ecology of the endangered Tasmanian Wedge-tailed eagle. His research includes monitoring the movements of juvenile eagles, using GPS transmitters.
The aim of the research is to clarify the behavioural ecology of the Tasmanian Wedge-tailed eagle and use this information to help improve management actions. The outcomes of this partnership will support our Threatened Bird Strategy by assisting us to address key questions such as; whether particular landscape traits increase the exposure of eagles to the hazard of collisions and electrocutions.
James is in the early stages of his research at the moment; however the data collected to date is already giving us a number of insights in to the movements of the juvenile eagles.
Raising awareness about the importance of reporting incidents of threatened birds of prey being injured or killed by the electricity network is also a crucial part gathering more data to support mitigation efforts. Last year, we ran sessions at all of our work sites to educate our people on how to report incidents.
We have also developed a mobile-friendly reporting form, which can be found at www.tasnetworks.com.au/reportwildlife
We appreciate you informing us of incidents involving threatened birds and our assets.
If you come across a dead bird of prey you believe may have been in contact with our assets, please fill out the form or report it to us on 132 004 as a matter of urgency.
We maintain over 20,000kms of powerlines, so we need the data captured in this form to help us identify high-risk areas and reduce the risk of incidents in the future. If you come across an injured animal in need of assistance, please contact Bonorong's 24-hour Wildlife Rescue Service on 0447 264 625 (0447 ANIMAL).
What are you doing under the voluntary offset part of the strategy?
While we're doing more than ever before, and making steady progress with mitigation work – threatened birds of prey will continue to be impacted by the electricity network. For this reason, one of the elements of our Threatened Bird Strategy is to support conservation activities.
In 2015-16, we partnered with Trowunna Wildlife Park to deliver its Wedge-tailed Eagle Rescue, Rehabilitation and Community Awareness Program. As part of the program, we funded the construction of a Tasmanian Wedge-tailed eagle on-display aviary for permanently injured birds, and the construction of a Tasmanian Wedge -tailed eagle rescue, rehabilitation and release aviary.
In 2016-17, we sponsored two projects at Bonorong Wildlife Sanctuary to help close the gap in resources available to rescue and rehabilitate large birds. This included funding for the construction of three low-stress, off-display, temporary holding aviaries suitable for large birds, such as injured birds of prey. We've also sponsored two veterinarians to receive expert training in large bird veterinary care at Healesville Sanctuary in Victoria. Through this training, these vets have been able to gain valuable knowledge and expertise, which can now be shared with other Tasmanian vets.
In May 2017, we provided in-kind support to the Raptor and Wildlife Refuge in Kettering, by supplying building materials to expand the centre’s aviaries and build capacity for the refuge to care and rehabilitate injured birds of prey.
Are incidents occurring in a specific area of Tasmania?
No. Unfortunately, incidents involving threatened birds of prey coming in to contact with the electricity network are not confined to a specific area of Tasmania.
Is there anything I can do to help?
Yes! It's crucial we're alerted of all incidents involving threatened birds and the electricity network, as well as any areas where threatened birds of prey are known to be frequently in the vicinity of powerlines.
If you come across an injured or dead bird of prey you believe may have been in contact with our infrastructure, please fill out the Wildlife Incident Reporting Form, or report it to us on 132 004, as a matter of priority. The more we understand about where and how incidents occur, the better equipped we are to make important decisions about how we protect these iconic birds into the future.
It's also important to acknowledge birds of prey can be killed or injured by a number of other means, including cars. In areas where there's a lot of carrion on the road, we urge motorists to drive slowly and be extra cautious of birds feeding on the roadside.