Is your new pet bird a boy, or a girl? It sounds like a simple question, but it's not always so easy to find an answer. You can find out if a dog or cat is male or female by "looking underneath" the animal, but with birds, this method is simply not going to give you any useful information. Whether you are trying to determine if this new bird will be compatible with your other birds, or, just trying to give this bird a fitting name, you will need to find out the gender of your new cockatiel or parakeet.
How to tell the gender of your cockatiel or parakeet:
(1)You find an egg in the cage with your one bird.
Only female birds lay eggs, so, if you have found an egg in the cage, and the cage is only used by one bird, then by process of elimination, your bird must be female. If you have more than one bird sharing a cage, and find the egg on the bottom of the cage, then you know that one bird is female, but which one? Some birds will ignore an egg after it is laid. Sometimes another bird in the cage will take an interest in an egg that isn't their's. If you have only one bird in one cage, and an egg appears, you can be sure that bird is a girl. Didn't find any eggs? Unfortunately, you cannot take that as conclusive evidence that your bird is a boy. It could be that your bird is female, but too young to lay eggs, or too old, or unable for some reason.
(2)You have two or more birds. You observe your birds mating.
For the most part, birds are going to choose to mate heterosexually. You can tell which bird is male and which bird is female by looking to see which bird is on the top when they mate. Male parakeets or cockatiels always will get on the top of female ones when mating. Look to see who is on top, and you may have another clue about the gender of your bird. Keep in mind though, that just like with humans, not all birds are heterosexual. If you have two birds of the same gender, sometimes they will try to mate with each other, especially if there are no birds of the opposite sex around. I have no idea how common this is "in the wild", I just know it does happen with domesticated birds.
(3)Check the markings.
On parakeets you can look at their cere, (where the beak attaches to the face and where the nostrils are located), and see the color. If it is very blue, your parakeet is a boy. If it is more pink, or pinkish gray, your parakeet is a girl. This only will work with adult birds. Baby parakeets and very young adult parakeets have ceres that are still able to change color, so, what looks like a female one day might start to look like a male later on, and vice versa. In a full grown adult parakeet, the cere will become one color and stay there. Realize, however, if the parakeet is white, or very light in color, this bird's cere will also be light in color, which can make determining the parakeet's gender just by looking at it's cere little more than a guess.
On cockatiels, you have to use another method. The ceres on cockatiels do not change based on the gender of the bird. Instead, look at the feathers on the bird's face. Most types of cockatiels will have orange or red orange circles of feathers, giving the bird the appearance of having "rosy cheeks". The brighter and more prominent the cheek color, the more likely it is that the bird is a male. Female cockatiels will also have the orange facial feathers, but they may be slightly less bright than what you see in a male. Cockatiels that are albino, or mostly white may not have any orange facial feathers at all, and you cannot use this method to figure out if the albino bird is a boy or a girl. Many pet shops will also tell you to look underneath your cockatiel's tail feathers, and see if there are stripes on the feathers. Female birds are said to have stripes on the bottom of the tail feathers. You can't use this method to find the sex of an all white bird, and it may be difficult to see if there are white stripes on the tail feathers of a very light yellow or gray bird.
(4)Listen for the singing.
You hear your cockatiel singing, making lots of different sounds, and trying to imitate some words you repeat to the bird? If the bird does this almost every day, then your bird is male. Female cockatiels will occasionally make sounds, but it is the male birds that are the singers.
Notice your parakeet making noises, all day long and into the night? Unfortunately, this is a characteristic of all parakeets, both male and female, and cannot be used as a sole determining factor in figuring out if it is a boy or a girl bird. This is especially true if you have more than one parakeet, because they tend to "talk" to the other members of their flock all the time. If you have just one parakeet, it's cere is definitely blue and has stayed that way for a long time, and you notice it has started whistling back to you, or imitating a specific whistle you do, then the bird is a boy.
(5)Get a blood test.
Still confused about what gender your bird is? Don't get discouraged. Figuring out the gender of a bird is not a simple thing. The only way to be one hundred percent sure that your cockatiel or parakeet is definitely a boy, or definitely a girl, is to have a veterinarian do a blood test and see. This test can be expensive, so most people only resort to this test if they are interested in breeding two birds. There are some kits on the market that will allow you to collect blood from your bird and send it into a lab to be tested for gender. These kits can be less cost prohibitive than a visit to a veterinarian, but there are risks. Birds can "bleed out" very quickly, and if you aren't careful you could harm or even kill your bird when you try to collect a blood sample. This will also be stressful for the bird, and even more stressful if you do not know what you are doing. Stress can also kill birds. If you absolutely must know the gender of your cockatiel or parakeet, it is much safer to have a veterinarian find out for you.
When in doubt, you could always just choose a gender neutral name, like "Pepper" or "Little One", which can feel appropriate for birds of either gender. Or, just go with the flow when "Max" turns out to be a "Maxine"!