Buildings are extremely deadly for migrating #birds every year, but they can be designed & updated to minimize collisions. https://birdcast.info/news/major-collision-event-in-chicago-4-5-october-2023/
Major bird-window collision event in Chicago, 4-5 October 2023 - BirdCast

Reports from the Chicago, Illinois area indicate that large numbers of birds died in collisions while major migration was occurring in the area on the night of 4-5 October 2023. Although details are still emerging, this event appears to be a combination of high intensity migration, adverse weather conditions for flying, and light and glass - a mix we know too well can be deadly. Turn off your lights, make your windows bird friendly!

Mortality for birds from collision with buildings is much higher than most folks realize. Although it’s worth noting that the toll is still vastly lower than deaths from cats.

Data from U.S. Fish & Wildlife. Also, bc it needs to be stated - this is not a post against cats. /2

@Sheril The biggest killing fields for birds are agriculture and urbanization+ human infrastructure. But cats are easier to target and to pretend the solution to it all is Keep Your Cats Indoors.