Are Nanday Conures one person birds?
My 6 year old 'Baby' conure has grown up in our household of 4. Baby gets along fine with all of us, and can say each of our names. Baby is quite sociable, and enjoys our individual company. However, Baby is territorial and will guard the one he's with by; threatening to and biting(!) anyone who attempts to take him from his perch on our respective shoulders.
Short answer: frequently yes. My 18 year old nanday is actually a two person bird, to the exclusion of virtually all others. My father and I are the only two who can touch or handle her without the risk of biting. She actually has declared a life-long vendetta against a few members of the family, and will readily fly at them, light on them and attack them if given the chance. She is particularly dangerous towards small children.