After a window collision, a bird just needs to rest for an hour or two. If it can fly away after that, it’s recovered.
Facts
Window collision victims suffer concussions, internal bleeding, swelling, vision loss and other injuries that may not immediately be obvious.
Even badly injured birds can fly away following collisions, only to die later.
Immediately place any window collision victim in a closed paper bag or on a towel in a closed box so it can’t escape, and bring it to a bird rehabilitation centre for proper treatment. Minimize handling and noise.