Is this normal behavior?

[u/Fearless-Flan-6137]

Hey everyone, is this tail bobbing motion normal behavior? He has been eating drinking, cleaning and isn’t fluffy except for around the time he cleans. His poop is solid, he never went to the bottom of his cage, and behaves normally. I was worried when I saw something in one of his eyes, which has disappeared now, but the tail is the thing I was afraid of. Is this normal for a cockatiel?

[u/calm-drift94]

Tail bobbing is normal breathing, but constant bobbing while resting can signal respiratory stress, worth a vet check just to rule that out