In what's turning out to be a rather shocking revelation, researchers have learned that the majority of animals can see pulses of UV light produced by power lines. Because these flashes are often frightening, they may be having a detrimental affect on wildlife around the globe.
Ultraviolet sensitivity is common among animals such as insects and birds. And as we're now learning, the same can be said for many species of mammals — except primates. While we can't see UV light, at least 40 different mammalian species can, a list that includes cattle, reindeer, hedgehogs, dogs, cats, bats, ferrets, and okapis. These animals — who have adapted to nocturnal conditions or low-light Arctic winters — have a special characteristic that primates lack: a visual pigment that's maximally sensitive below 400 nanometers. What's more, some animals can still process UV even without such a pigment if they have eyes that can transmit at certain wavelengths.
Now several years ago, scientists discovered that UV cameras can pick up the coronal discharges of power lines. They appear as bright flashes of light, appearing a bit like this:
Actually, because of the camera's relatively limited UV range, animals probably see these flashes with even greater intensity.
By coupling these two discoveries together, scientists now believe that most mammals see power lines in this way — a discovery that's helping to explain why some animals go out of their way to avoid them. The Guardian reports:
Dr Nicolas Tyler, an ecologist at UIT The Arctic University of Norway and another member of the research team, said: "The flashes occur at random in time and space, so the power lines are not grey and passive, but seen as lines of light flashing."
He said the discovery has global significance: "The loss and fragmentation of habitat by infrastructure is the principle global threat to biodiversity – it is absolutely major. Roads have always got particular attention but this will push power lines right up the list of offenders." The avoidance of power lines can interfere with migration routes, breeding grounds and grazing for both animals and birds...
...Around the world, Tyler said: "There are hundred of examples of animals avoiding power lines. Now we know that, not only do these clear-cut corridors mean exposure to predators, at the same time there is this damn thing flashing at you."
Jeffery said burying all power cables would be unrealistically expensive but added that one idea would be to put a non-conducting shield around the cable to screen it from view. The UV light, which is caused by electricity ionising the air around cables, are a major source of inefficiency for electricity companies and also cause the hissing or crackling noises sometimes heard.
Wow. It's increasingly obvious that we humans see, smell, and hear a very small portion of what most animals do.
More at the Guardian.