Utah State University Extension
This fact sheet explains the problem of birds colliding into windows, why they fly into windows, windows that pose the greatest threat, what you can do to reduce the risk, and what to do if you find an injured bird.
Cowell, Samuel; Dietrich, Cameron; Sullivan, Kimberly; and Messmer, Terry, "Reducing the Risk of Birds Colliding into Windows: A Practical Guide for Homes and Businesses" (2017). All Current Publications. Paper 1661.