Bird collisions are caused by tall buildings.
Facts
Because most collisions occur at the height of trees and other vegetation, the height of a building has little effect on collision risk. The amount and type of glass, along with a building’s surroundings, are far more important.
Tall buildings usually also have wide circumference and thus a large amount of glass in the high-risk zone, which is from ground level up to about 16 m, depending on the height of trees. This means that individual tall buildings can be responsible for a lot of collisions. But together, they account for fewer than 1% of bird-glass collisions.1
The other 99% of victims are killed at residences and low-rises buildings, simply because there are so many more of those types of buildings.
Collisions per building type

- Loss, Scott R., Tom Will, Sara S. Loss and Peter P. Marra. 2014. Bird–building collisions in the United States: Estimates of annual mortality and species vulnerability. Condor 116:8-23.
https://doi.org/10.1650/CONDOR-13-090.1 ↩︎