High voltage power lines

The BBC reports that a team of researchers says that high voltage power lines produce UV flashes which most animals can see, and surmise that this can discourage animals from coming near the lines.

"It has always been assumed that power lines - masts and the cables strung between them - were passive structures standing immobile in the terrain, and therefore inoffensive for animals," said Dr Tyler.

"As a result of this work, we now consider them as chains of flashing light stretching across the tundra in the winter darkness, and that's why the animals find them so offensive."

The random and unpredictable nature of these flashes were particularly problematic, he added, as the animals could not easily adapt to them.

Apparently reindeer avoid the structures: "The animals keep as much as 5km (3 miles) from either side of the cables."

Do they avoid them in the daytime too? Corona flashes can be startling at night, but we generally had to turn out the lights and get dark-adjusted when trying to figure out where the discharge was. (Grad students peering in the dark close to a frame covered in 6000V wires, looking for slowing spots--what could go wrong?)

Also, 3 miles is quite some distance.

I'd have looked at noise. Corona often makes noise. And the noise rate from a semi-infinite wire won't change much with distance, until you get far enough away that the terrain starts to randomly block the sound: it will always be buzzing at you.

If the terrain starts to significantly block either sound or light when the visual angle to the top of the tower is about 1degree, and the towers are 30m high (pulling all numbers out of the air), I'd expect the critters to hover somewhere around 1.7km away to avoid the racket or the glow. So the buffer distance isn't crazy.

I didn't realize that so many mammals could see UV. I wonder what windows look like: partly transparent, partly reflective? What other little things glow that we don't notice?