The passage states the three ways which can avoid birds to fly through glasses, the first one is the one-way glasses,which is like mirror, if the bird can`t see the other side of window , they will understand the window is a barrier which can`t be through. Yet the speaker in the lectrue disagree with it because, the One-way glasses is like mirror, therefore glass can reflect the sky and tree where the class is facing, Thus the bird see it, they can`t understand it is a glasses, they will consider it as sky or tree and they will try to fly through it. 
The second solution is the colorful glasses which has little stripes painted over the glasses, to notify the bird there is glass over here, to let them understand, on the contrary, speaker disagree with this idea again, 
the reason is that when the bird see these little stripe on the window, they will think these little stripes are holes and they will try their best to fly through it, If you want them to really notice there is a glass, you need to paint the stripes small enough, yet too much stripe will let the room too dark. now,It`s bad for mankind. so the colorful glass is not the effective solution.
The last one is create an artificial magnetic field to stop the bird when they flying. we all know that the bird use magnetic field to navigate or orient the direction, but It only work when they get a long distance trip if they only travel one spot of city to another spot, they still use their eyes and lightness of the sun, to conclude, the artificial magnetic field is not effective either.