If you don't know definately that the bird bit her, it could be something else. Small dogs (of which I have 3 and work with a maltese rescue), can jump down and have their patella (knee cap) out of place when they do this. Then their back hurts very much and they will limp. If the patella didn't come out, they may have strained their back. This has happened twice for me with my peke-a-poo and once for my maltese. I ended up having to have knee surgery on both. So, if you don't know for sure about the bird bite, I would take her to the vet. If you have some baby aspirin, you can give her 1/2 a tablet - maybe hidden in cheese, to see if that relieves the pain.
hth.