Having one cockatiel is like having one potato chip: soon you want more. Adopting a second 'tiel isn't as simple as bringing him home and putting him in a cage with the female you already have. Just because they're the same type of bird doesn't guarantee they'll be compatible companions.
Minds Of Their Own
Male or female, most cockatiels are friendly and tolerant. Your pair could get along from the start, but it isn't a sure thing. Your birds have their own personalities and, as happens frequently with humans, those personalities sometimes can clash. Not every cockatiel pair are certain to become a loving couple or best friends. You even may find that the two you're attempting to match can't tolerate each other.
A Love Match
If you want to put your male and a female cockatiels together in hopes of creating a love match, you stand a good chance of playing Cupid successfully. Introduce them slowly, keeping them in separate cages for a week or two to give them a chance to get to know each other while still in their own individual spaces. They also should be given the chance to play together outside of their cages in a neutral spot. If they get along well, provide Romeo and Juliet with a new larger cage and watch to see if they continue to bond.
If They Don't Bond
If you've allowed your male and female cockatiel a couple of months to get to know each other and they still haven't warmed up to one another, don't force the issue. Continue to keep them in separate cages, giving each of the birds individual attention and play time. If they can be together in the same play area outside of their cages without a fight breaking out, you can allow them out at the same time. There's always a chance that their relationship may change and they might grow to accept each other eventually.
Setting The Mood
If your male and female cockatiels end up being a compatible pair, there's one certain outcome: cockatiel babies. If you welcome the flitter-flutter of little wings, you can encourage the couple to go forth and multiply by setting up the right conditions. Sure, playing some Barry White might not hurt, but what will help set the mood is a nesting box and plenty of daylight, around 15 hours each day. Enhancing their diet will help, too. In addition to their quality 'tiel mix, give them plenty of soft foods, like sprouted seeds, cooked rice, beans and vegetables, and provide a mineral block or cuttlebone to increase calcium for your female. Talk to your vet about vitamin or other mineral supplementation before giving them to your birds, as they may not be necessary. It's always wise to consult an experienced veterinarian regarding the health and treatment of your 'tiels.