Young cockatiels look so similar that it is often hard to determine the male from the female until the first time they molt and their adult colors show. Immature cockatiels look nearly the same and flipping the birds over like a dog or cat will not provide the owner with any information she can use. Finding the sex of your bird can help you ensure that your bird receives an appropriate name or help ensure compatibility with other birds in the home.
Know the age of the bird. This will help determine whether or not it has gone through the first molt. All cockatiels under the age of six months will look like females. Birds older than six months have molted once; the true colors should be more apparent.2
Look at the face. The male of the species normally has a bright yellow face highlighted by bright orange cheeks. Females tend to have a white or gray face with dull orange on the cheeks.3
Observe the tail feathers and the wings. Females typically feature dark bars on the underside of their tail feathers, while males do not. Spots on the underside of the wings will normally stand out on females, but not on males.