Birds can live for a long time, so it's important to be sure that you can look after them in the long term. As they are such a diverse species, it's important to discuss the breed you may be interested in with the breeder beforehand. For example, you should consider any specific dietary requirements; where the bird has been reared and kept; whether the bird is tame etc.
Typically, most birds are either imported (and caught in the wild), or are aviary bred. Adult birds and some young birds caught in the wild find it hard to adjust to living in cages, and there is also a greater risk that the bird may be carrying a disease. Animals should always be imported according to local animal quarantine laws.
Birds that are bred in captivity will be much more used to domestic life. If the bird has been hand-reared, it will already be hand tame. This means they are likely to be more expensive, but will be easier to introduce into the home.
Many dealers and breeders ensure that birds have been tested for certain diseases. As avian medicine is particularly specialized, it's important to consult your veterinary clinic before visiting, to check that a veterinarian experienced in avian medicine is available.
Things to consider
Because of their efficient respiratory system, birds are very susceptible to poisonous gases, such as burned plastics and so forth.