I can't actually read it but it looks like it might be a price tag lol.

no price tag

It was one of those days you all had with your beloved fid, when he/she is being a brat and a nuisance... Bubu was on fire all day and then he went to sit on the laptop top looking angelic (and pooping on it).
The temptation of sticking an ASS sign on his back was irresistible

Now that I know what it says I can see it! That's hilarious.

A price tag would say "Bird for sale. Cheap!" which can also be a way to say that your bird is annoying you. I was thinking along those lines.