Glass is a great material for build the building, but it is very peril for birds. That because of those birds always try to fly into the glass because they can't notice it is a glass.
  Therefore, some liable enterprise are trying to reform the glass by using unidirectional glass, change the glass color or magnetic field but it is useless.
  Unidirectional glass can lead to the function of mirror, can reflex the things oppositely. So the bird will think it is a sky or anything else and get close it it.
  Besides, to change the color of glass is not a good solution too. The remain glass that don't have color will let the birds think it is a hole which can go inside.
  In addition, the magnetic field can't use ether. The . In fact even the birds have magnetic fields too but it can only use in a long distance such as migration. The magnetic field can't influence them in the small distance.