Nips just one member of the family

[jrichter]

Since I am a new bird owner I thought I would ask this question:
What would cause my green-cheek conure to nip (bite) just one member of my family (my daughter)? The bird does not appear to be afraid of her in any way, and he(?) comes to her whenever she is near the cage and talks to the bird. The biting pressure is doing down over time, but I am very curious as to this behavior toward one person (who likes the bird very much).

Thanks!

James Richter
San Antonio, Texas