1. As a general rule, 2 birds of the same species do best together, and usually of the opposite sex. There are many exceptions and quite often this is decided by the individual case, personalities of the birds, and past experiences of each bird. 

2. Budgies, Cockatiels, Lovebirds, and Canaries,  for example, usually love the company of other birds. If housed together, starting at a fairly young age, putting birds of the same species together can usually work.  It can even work with birds of the same sex.  However, if they are of the opposite sex and siblings, they may want to mate later. It would be preferable to breed birds with from different bloodlines.  Even birds who appear to get along at first may become aggressive during breeding periods.  Each bird owner is responsible to observe these developments to avoid problems.

3. Putting 2 parrots of different species together in one cage can be very tricky. Sometimes birds who know each other very well over a period of time will display affection such as preening or feeding each other. We need to remember that most parrots are territorial by nature. Although they get on well on a neutral area, such as the couch or playpen, going inside each other's personal cage might spark fighting. Also when one of them  decides it is breeding time, fighting could result in injuries, even when birds have normally got along well.. This can happen very fast, especially to an owner who has been lulled into a sense of security by the birds youthful or non breeding behavior. Usually we recommend housing different species in their own personal space. (cage)

4. When a pet owner has only one bird, quite often one may wish to buy another parrot to keep their pet company while at work. This endeavor should be approached with caution and patience. The end result should be two birds who enjoy each other's presence, and  perhaps vocalize and take great delight in each other's activities. We have found this works best when two separate cages are provided and each bird has their own possessions, such as toys. Each bird is an individual and needs attention and personal care and love. Some people think that acquiring a second bird will reduce the time needed for their original pet. NOT AT ALL! Needed time input for 2 parrots will double!  

5. In some cases, introducing birds to be (hopefully) mates, can be accomplished by placing the birds beside each other for a monitored period of time in separate cages. With this method, the owner must monitor "play" time in a neutral zone,  and allow the relationship between the two birds to develop naturally. This can take weeks,  months or even years.

6. There are so many variables, different species, and behaviors involved in putting parrots together, that it is usually best to speak with an avian veterinarian, or other professionals before playing birdie matchmaker