why do my parakeet bite

Question
I have a female parakeet i just got. A week later she started likeing me and everyday when i come home for school she will be waiting by the cage door ready for me to take her out. But lately i stop doing that and now when i try to take her out the cage she bites me, even when i try to rub her like i used to  she wont let me why is that?

Answer
Dear Rome,
thank you for your question.
It's hard to judge behaviour without actually witnessing it. Parakeets bites for several reasons:
1. because their are scared, but your parakeets seems to be tame, so i don't think that's the reason
2. to be left alone, this may be why your parakeets bites. Try letting her come to you when she wants to, don't force her (even gently), it may be better to handle her only when she's outside the cage so that she has more room to move around if she doesn't want to be handled. She may feel  hemmed in when you try to take her out of the cage
3. when they are sick - if a bird is feeling sick, it wants to be left alone, like humans. Birds are very good at hiding illnesses, but sleeping a lot and sitting around and fluffing up a lot can be first signs of an illness. If she does any of this, you should see an avian vet with her, you can find one here:
http://www.birdsnways.com/articles/abvpvets.htm
http://www.birdsnways.com/birds/vets.htm
4. during courtship, parakeets bite each other. It doesn't hurt them because of their feathers, but for humans it can be painful. But what you describe doesn't sound like that, she would interact with you first and then get so excited that she bites.
I hope I was of some help to you
Jennifer