Bird–window collisions (also known as bird strikes after the aviation term or as window strikes) are a problem in both low- and high-density areas worldwide. Birds strike glass because reflective or transparent glass is often invisible to them.[1] Previous research estimated that between 100 million and 1 billion birds are killed by collisions in the United States annually,[2] but a 2024 study on the survival rate of bird-building collision victims indicates that previous research was vastly underestimating the number of deaths caused by collisions, and in actuality well over 1 billion birds die from collisions in the United States every year.

https://en.wikipedia.org/wiki/Bird–window_collisions

The ducks that were able to walk away were lucky, probably not flying at full speed yet. And they were still probably concussed afterwards.