The Cockatiel
The cockatiel (Nymphicus hollandicus) is an Australian native, second in popularity only to its country-mate, the budgie. This bird is wonderful for the beginner or novice bird owner, who will want a docile, friendly, generally quieter avian companion, as compared to birds of similar size that can be quite a handful and louder, as well as more expensive. Because the cockatiel is so easy to breed, you should be able to find quality, handfed or tame birds readily available in your area, no matter how remote.
Even though cockatiels are available in dozens of mutations, the normal gray and the lutino (yellow) seem to be most popular. Other mutations, such as the pearl and the pied are second in popularity, with the fancier mutations, such as whiteface and albino following just after.
Cockatiels given enough human interaction daily do not need a companion, though they do enjoy one another's company and will not lose their pet quality if housed together as long as the owners continue to play with them daily. You may want a pair if you're a busy family or an individual who will not be home for most of the day. A pair will be noisier than a single bird, and though cockatiels are not loud, they can be persistent whistlers, and some males may even learn a few words.
As for housing, bigger is better for this active bird, whose wild cousins fly many miles a day in search of food and water. A cockatiel housed in a small cage will become extremely unhappy and is more prone to health problems, such as obesity, and can greatly reduce its lifespan, which is up to 20 years if given the proper care. Make sure that the cage has the proper bar spacing for the cockatiel, whose head is quite narrow and can become stuck between the bars, causing the bird to panic and possibly break its neck. The cage should have a metal grating on the floor to keep the cockatiel away from his droppings and should have doors that latch securely—these birds can be escape artists and are talented flyers, able to get away fast.
Cockatiels often benefit from a "sleeping cage," a smaller cage where they spend the night in a quiet room. Cockatiels will also benefit from a cage cover, though some of these birds experience "night frights" in the darkness that cause them to thrash around the cage, often causing injury - usually, the addition of a nightlight in the bird's room helps with this phenomenon.
The cockatiel has a tendency to become obese, sitting at the seed dish all day and picking out its favorites. The cockatiel fed an all-seed diet will only live out half its lifespan, if it's lucky. Provide a variety of foods for a balanced diet.