Many animals see power lines as lines of bursting, popping lights. That's because they can see ultraviolet light that's outside the spectrum of human vision..
In a study published earlier this year in the Proceedings of the Royal Society B, scientists analyzed the eyeballs of 38 different mammalian species. What they found suggests that most mammals can, in fact, see UV light -- including dogs, cats, ferrets, and reindeer. Unlike humans, these mammals have lenses that allow UV light though. Even though they lack the specialized UV-sensitive type of cone, the other three kinds of cones can combine to make up for it. (In fact, when people have the lens in their eyeballs removed -- either through injury or surgery -- they're able to do the same trick, and report seeing UV light as something like a pale violet.)
One example is reindeer, whose habitat has become severely fragmented by growing infrastructure in the Arctic, including power lines. Up to now, though, exactly why reindeer avoided power lines was a mystery. But in the dark arctic winters, such light reflecting off the snow can be blinding.
Power lines look like terrifying bursts of light to animals