The fleshy, bulbous area right above a budgerigar's beak just below the eyes is call a "cere." This is where the nostrils, called "nares" live and it appears to be a ridge that connects the beak to the bird's face. An interesting fact about the word "cere." is that it comes from the Latin term cērāre, which means "wax."
Not all birds possess a cere. Parrots, doves and pigeons do as well as raptors and some other birds of prey.
Experts don't really know what the purpose is for the cere but most experts seem to think it has to do with the bird's sense of smell. But it does have some interesting characteristics. The cere on an adult parakeet or budgerigar as they are also known is a pretty good indicator of the bird's sex. Makes have a darker colored cere than the females. The issue with consistency in this indication is that lighter colored birds will have a lighter colored cere so while in theory cere color is a fairly good indicator of the sex of the bird, it isn't that way in all budgies. This only applies to adult birds as the cere color in juveniles changes as they age.The cere color can also change in the female when she is in breeding condition. When she is in season and is interested in breeding, her cere might turn brown in color. But this isn't always the case. Some female's ceres don't change color at all.
Another indication of sex especially among pigeons is the fact that a male's cere is usually larger and more pronounced than the cere on a female.
Bird watchers, also known as Birders often use the cere as a means of identifying different types of birds in their never-ending quest to see different types of birds.
In any case, if you feel it is important to find out the sex of your budgie, it is best to get a DNA blood test done. The accuracy of these blood tests are about 99% and while not completely fool-proof, they are overall about as accurate as you will find which trumps any other method of discovering the sex of your bird. It's fast and only takes a drop of blood to determine the sex of your bird. Surgical sexing used to be the only way to determine the sex of a bird with absolute certainty but this method is rather invasive and can be risky. This method is not considered obsolete and necessary due to the accuracy of the current blood test.
Some ceres are extremely large and ornamental. English carrier pigeons have a huge, bulbous cere right on the front of their face that resembles a brain somewhat. Many people down't care for this appearance, but apparently there are some pigeon fanciers that find this pleasing.
Another interesting feature about the cere is the fact that the condition of the cere is a telltale sign of illness.
It is a go-to observation avian veterinarians first look at when examining a bird. If there are any signs of irritation, swelling or inflammation, the vet will be promoted to do more investigation looking for possible respiratory issues. Other problems with the cere indicating illness is a chapped cere as well as what appears to be a runny nose. Chronic respiratory illnesses and infections may cause the cere to sweep and become impacted with pus from the infection causing distortion of the cere. These plugs of pus are called rhinoliths are more commonly observed in African Grey parrots but of course this condition can pop up in any species of bird. It is important that the avian veterinarian determine that this is indeed an infection and not a tumor or what is called a granuloma which is essentially an inflamed tumor. This can be corrected with putting the bird under general anesthesia and flushing out this accumulation of pus caused by the infection.
The cere is a one of the more obvious parts of your bird's anatomy you can observe that indicates the bird's health. Keeping an eye on it for sweeping, dripping or any type of discharge is a good practice.
Edited by: Patricia Sund