They reached the end of the passageway and saw before them a brilliantly lit chamber, its ceiling arching high above them. It was full of small, jewel-bright birds, fluttering and tumbling all around the room…
There is no zooming in this moment.
You are looking for the Winged Key, which is a silver key with blue wings, one of which is broken. Only some of the keys in the picture actually move around.
All you can hear in this moment is the sounds of all of the wings fluttering.