I've noticed that birds will disappear from their cage if you relaunch the game. The birds seem to be 100% guaranteed to vanish if the cage is far from the Florid Postern (e.g. Oasis, Pig King). However birds closer to the Postern seem to have a chance of not vanishing (I think that they will disappear if you reload close to them, but will not if you reload far away).
This is in the Return of Them Beta. (Is there a separate bug tracker for it? Is this just general DST bugs?)
If you need I'll try to get a video.
Steps to Reproduce
Place bird in birdcage. Save and quit Reload. Voila! No more bird
This issue has been fixed in either a future version or updated in a previous version.