tiel behaviour

Question
I have 2 tiels. both males 2 1/2 yrs old. One grinds his butt on the lettuce I put on the cage. Is that sexual behaviour?
One more, why does one pursue the other, following him so close he steps on his tail. He does not let up and is clearly irritating the other bird. Is this mating behaviour or "power tripping"?

Answer
Hi, Lisa.  Thanks for posting!

The butt grinding on the lettuce could be the bird masturbating with the lettuce or the bird is getting itself wet with the lettuce, if you put the lettuce in the cage wet.  By the way, if this is iceburg or romaine lettuce, it has no nutritional benefit for your tiels.  Offer kale, mustard greens, spinach or similar.

The following around is most likely power tripping.  Parakeets often do this to tiels when they are housed together.  Is the one following also the bird grinding it's butt on the lettuce?  This might help explain what's going on.

Chrys