His ability to produce the signal that conveys that information is the part that tells her if he's capable of helping feed the chicks.
BTW, all the parrots of the same species have just about the same genes ~ maybe a few differences here and there with methylation ~ but same same!
My concern with parrots is they have more advanced brains ~ and yet they don't do very much different from other birds ~ in fact, my son prove that you can call a parrot down from a tree to sit on your shoulder just as you might a crow or a duck. Surprised his girlfriend I'll tell you that, but not me ~ or our other relatives.
Seriously, being a bird is not a mentally challenging occupation
You dont think the female Parrot or Mockingbird chooses the best possible mate conveyed by superior songs, and some other display behavior among her suitors of the same species? Surely not.