I have a female budgerigar whose beak recently changed colour - its tip turned brownish-black. There are no bulges on the beak, nor does she have any other symptoms. I previously had a budgie whose behaviour changed dramatically as it was traumatised after a visit to the vet, so I'm rather scared of taking this one anywhere.
What could cause this beak discoloration in my budgie? Is there something I can do to help her, aside from taking her to the vet?
Edit: She is between 1 and 2 years old. I give her a commercial mixture of bird seed, consisting predominantly of millet (78%) and other types of seeds. I also give her a commercial mixture of parrot minerals.
The beak pigmentation looks like this: