Summarize this article in one sentence.
Adding a mirror in the cage of your budgie can keep the bird entertained for hours. They love to look and talk at their reflection but be aware that there are debates about potential psychological damages.  Instead of a mirror, consider a second bird. Budgies love company and will probably welcome a new friend. A mirror will most certainly with male, often also with female budgies lead to crop infections as parakeets regurgitate to feed their mates. A mirror (the feeding bird itself) will not provide the needed feedback that has to come from a real mate. If you decide to install a mirror, make sure that it's fixed to the cage and doesn't present a risk to your bird. Your bird will love the interaction and the games and is likely to become very chatty. Move your finger in front of it–– if it is shaking its head in the same direction, it means that it loves to play and is very active. Once the bird is at ease with you and its environment,  you can let it fly in a room with all of the windows and doors closed. To call it back, switch off all the lights and the curtain of one window open, but remember the window must be closed. The budgie will be attracted towards the light. Hold it gently and put it back inside the cage.  Make sure that the bird is safe. Put the cat or dog away and look out for potential escape routes. Think about your own hygiene. Your budgie is likely to defecate on the floor. Don't let it fly in a carpeted room. If there is feces on a solid surface, you can wet a paper towel and wipe it away.
Weigh the pros and cons of a mirror. Talk and play to the budgie often. Let the budgie fly in a room.