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I had purchased my female budgie when she was about 4-5 months old, and had tamed her a bit, just enough for her to be taken out of the cage, step up and be right beside me. I think it was around her next moult when her cere had turned brown did I started noticing the signs. Though she is aggressive, she had a small wing injury after her blood feather had fallen out (mind you, it wasn't from a fall or an impact. I was just holding her in my opened palm and noticed blood when she had flew) so I had to often take her out of her cage and clean her wing a bit to avoid infections.
During the days when I take her out, she would be willing to sit beside me or on my shoulder, but she just hates seeing my hand anywhere near her. I do hand feed her, though.
And then it evolved into something else....Besides her, I have another female budgie, one which is more passive and easier to tame. I began to notice that even if I just walk pass their cage, my first budgie (the trouble maker) would avoid me to the point where she would run along the perch and end up pushing the other one off. It's like she REALLY hates my presence all of a sudden. I am trying to gain back her trust, but it's so hard...She doesn't bite, but she just runs away :( Any tips?