The sun conure will vibrate its mouth against different objects to show affection. This behavior is common among normal, healthy and active sun conures. Periodically, it may regurgitate food while vibrating its beak against you. However, excessive regurgitation can be a sign of a more serious condition.
The vibrating motion in question is similar to what conure owners call "head bobbing” and occurs when your sun conure nudges its beak against you in a quick, repetitive motion. This quirky behavior is a display of friendship toward its human guardian. Sun conures may select a favorite toy to vibrate against during playtime.
It is most likely that this behavior is learned as a chick. In the wild, the mother bird (hen) regurgitates partially digested food to feed her chicks using this same motion. Hand-reared chicks fed with syringes may exhibit this behavior, too.
During adulthood, sun conures offer this learned and biological behavior to their favorite companions. In most cases, it is a sign of love and devotion. In short, consider yourself part of the flock, especially if the conure gives you some pizza snacks from lunch.
Take note when your sun conure exhibits this vibrating motion. Do you see it doing the same with a toy? Does it pay more or less attention to that toy? Learning body language can be key in getting to know your sun conure's likes and dislikes. If it pays more attention to the things it vibrates against, it usually indicates normal, happy behavior.
As with most parrot species, excessive behavior may be symptoms of an underlying illness. Make note of when and how often your sun conure displays this behavior. Does it do it only during certain times of the day, or after a certain activity? Also, make note of behaviors that accompany any behavior in question. When in doubt, ask your avian vet.
Regurgitation associated with love nudges may disappear with maturity.