According to the sites I visited, it does not appear that all parrots dislike mirrors. Rather, some seem to like them, although it may depend on the specific breed of parrot you own. Perhaps your parrot is particularly territorial and is "defending" its habitat from the other "bird" it sees in the mirror. Or your parrot may be aggressive by nature, as according to an article on MedicalNewsToday, "Parrots' Behaviors Mirror Human Mental Disorders."

According to ParrotChronicles, "Mirrors can also ease the anxiety parrots may feel when left alone. Few people realize how unnatural it is for a parrot to be left without a companion while the owners are at work. In the wild, parrots have a mate, partner or friend by their side almost every minute of every day of their life." However, if your bird is scaring you and trying to hurt you, your best bet is probably to take him to a vet or ask an animal behavior specialist why he may be acting in such a manner.

My African Grey Parrot is a big "chicken" when it comes to mirrors. He backs away from them and hides in the corner of his cage. However, he doesn't like new things. It takes him a while to get used to new toys that we put in his cage, even new treats. He will usually warm up to them eventually, after they stay in his cage for awhile.

It actually depends on the parrot. Some parrots like to see their reflection, some don't. Usually birds like to see their reflection because it gives them a sense of friendship with the reflection in the mirror. But some birds feel it's a predator they're seeing. If your bird doesn't like a mirror don't put it by the mirror.