The Cockatiel is one of the best known and most loved of all the parrot family. They are cheerful, friendly and easy to train; making them one of the most popular pet birds throughout the world. As pets, they are second only to the Parakeet (Budgerigar). It is actually an unusual member of the Cockatoo family. They range from 10 to 12 inches in length with a slender body and long pointed tail, making them the smallest member of the Cockatoo family. Cockatiels are native to the outback regions of inland Australia, and favor the Australian wetlands, scrublands, and bush lands.
Adult Cockatiels are sexually dimorphic, meaning you can visually see the difference in the sexes. This is only evident after the first molt occurs about six to nine months after hatching: the male loses the white or yellow barring and spots on the underside of his tail feathers and wings. The gray feathers on his cheeks and crest are replaced by bright yellow feathers, while the orange cheek patch becomes brighter and more distinct. The face and crest of the female will typically remain mostly gray, though also with an orange cheek patch. Additionally, the female commonly retains the horizontal barring on the underside of her tail feathers. This is one of the few times that you will find that the male is louder and more verbal than the female. (Ha! Ha!)
Cockatiels have the distinctive crest of the Cockatoo family. This crest is used to express the bird's mood. The crest is dramatically vertical when startled or excited and relaxed when the bird is at ease. If angry or defensive, the crest is flattened close to the head. This is when you should give your bird his space, because you just might get bit.
Cockatiels can be found in a variety of color mutations. In the breeding world their has been alot of excitement about the new color variations. As well as the normal grey, there are pieds, cinnamons, lutinos and pearlies. You can also find whiteface, silvers, albinos (lutino-whiteface), fallows, and there are now yellow-cheeks and orange-crested. Plus there are combinations of all of the above.
For a general information sheet on Cockatiels click the above link. These are available in Adobe PDF format. If you do not have Adobe Reader, click here to get it. It is a safe, free download.