From the former Chairman of NTT
After Nippon Telephone and Telegraph spent much effort to develop a new aerial cable an unusual enemy appeared:
"We discovered that a species of bird, the Spotted Woodpecker, liked to peck holes in the hard polyethylene sheathing. We have never figured out why the bird should do this, but it certainly seemed determined to peck its way through the plastic sheathing."
"At first we thought it was looking for insects, then perhaps it was using the cable to sharpen its beak; someone even joked that it was, literally, 'wiretapping.' Although we dedicated a good deal of research to this problem, we failed to come up with any convincing explanation for the bird's behavior."
"Many of our cables in mountainous Hokkaido and Nagano prefectures were continually damaged by this industrious bird. And once it had made one hole, it would not stop until it had riddled the cable with holes for hundreds of meters on either side."
"We tried setting up scarecrows and stringing piano wire above the cables to mate it more difficult for the birds to perch on them, but all our attempts failed. In the end we were reduced to installing special cables coated with an extra layer of protective steel."
Telecommunications: NTT's Vision of The Future, Yamaguchi, (1991) NTT Publishing Company, Tokyo, 94