What changes the cages answer
Skip mirrors as the default cage toy. If a bird is lonely, bored, or hormonal, a mirror can make the problem harder to read instead of solving it.
A reflection is not a friend
A mirror does not respond like a real bird. Some birds court, guard, feed, or obsess over the reflection and become stressed when it never behaves normally.
Watch for fixation
Remove the mirror if the bird guards it, screams when away from it, attacks people near it, regurgitates constantly, or stops exploring other toys.
Use better enrichment
Foraging toys, safe chew work, training, and calm social time give the bird something healthier to do.
Companionship needs a real plan
If the bird truly needs another bird, that means quarantine, compatibility, space, and cost, not a mirror.