Monday, 2 January 2017

What do animals think of electricity pylons?

Britain's beauty spots are continually threatened by the prospect of strings of electricity pylons 'scarring a cherished landscape steeped in history'. The National Grid has agreed to spend £460 million on burying cables that would cross the Lake District National Park [1] - that is about £15 per household that we will pay through our electricity bills for just this one case. If this is a purely aesthetic consideration, I think it is rather expensive. However our national parks aren't just for our pleasure they are for wildlife and biodiversity too. So, what do the birds and the deer think of electricity pylons and wires crossing the landscape? We know they see these things in a different light - literally! Also they don't like places that are noisy. Perhaps 2017 is a good time to think about how we can make our technology more friendly from the point of view of the species with which we share our planet.
You may think these pylons ugly but what do animals think?

For a long time we did not understand why many animals avoid high voltage power lines. It is not because they find the presence of human technology of itself offensive. After all, wild birds and mammals are happy enough to take residence in our gardens and urban wastelands. When pylons cross forests you get a corridor of clear cut trees and this is likely to be a big part of the problem. Small animals don't like to leave the forest cover that hides them from predators. They can go round small clearings but not lines of pylons many miles long. The answer there could be to allow ground cover to grow under the pylons. But we know that animals avoid pylons in other areas too.

A couple of years ago we found another potential issue - high voltage lines produce flashes of ultra violet light which are probably quite scary. We can't see these but many animals can including cats, dogs, hedgehogs and deer. The flashes are caused by electrical effects that also cause buzzing and hissing. We can fix the problem by wrapping the cables in shielding. This also reduces transmission losses. Another solution is to use DC current for high voltage transmission [2].

It is hard to work out what animals are thinking so I was amused and delighted in equal measure by research from Southampton University into how robins rate places. They introduced an artificial robin into different parts of a park and measured how ferociously the resident birds threatened the interloper. The theory is that robins in the best areas would defend more vigorously - I am not sure if this is because they are worth fighting harder for, or because they are already claimed by the most aggressive, bullying birds. Either way, the effect is the same. Not surprisingly it turned out that robins prefer places away from city noise and lights [3].

I don't agree that the value of a landscape is reduced by £460 million pounds by the introduction of a few wires and pylons. But I do believe we should be sensitive to the needs of other species that share our landscapes. They don't share our romantic aesthetic view of nature but they do value peace and quiet. In the case of pylons, that means allowing strips of undergrowth below the wires, so that shy animals can cross the gap, and also putting shielding around the wires themselves to avoid UV flashes and buzzing. This is much cheaper than laying underground cables!

[1] Last known Wordsworth descendant joins fight to stop Lake District pylon (Guardian) 1 Dec 2017
[2] Animals see pylons as glowing, flashing bands. (Guardian) March 2014
[3] Noise pollution and street lights are affecting the song of the urban robin (Yahoo News) Dec 2016

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