why do birds fly into windows

Birds fly into windows primarily because they cannot perceive glass as a solid barrier. They often see reflections of the sky, trees, or nearby greenery in the glass, which they mistake for real habitat or open space, leading them to fly toward it. Additionally, birds may see through transparent glass to plants or other attractive features inside a building and attempt to reach them. At night, artificial lights can also attract migrating birds, causing them to collide with windows. Aggressive territorial behavior can also cause birds to attack their reflection in the glass. These collisions often result in serious injury or death for the birds due to the impact or subsequent vulnerability to predators.