Budgies are gender dimorphic in only one way: the cere. The ceres of young budgies under 8-12 months are all about the same: a bright pink or violet color. As the budgie matures, the cere changes according to the budgie's sex.
- Females - White/light-blue, tan, or brown cere. This is true for all varieties. With the development of brown color is a flaky texture. This can build up to be about a centimeter thick.
- Males -
- Blue or purplish-blue cere in normal varieties only.
- Bright violet or pink (does not change after youth)
- If your budgie is less than one year old, the above rules are not applicable. The cere usually begins to change before one year. However if your young budgie's cere develops the brown flaky appearance characteristic of female budgies you can be sure it is a female. You can also look at behavior to determine gender. Males often bob their heads, sing, and are usually more active and outgoing. Females are usually snitty and bossy over other budgies in the cage, and rarely sing. Females also usually make loud mad budgie sounds. Males sometimes make this sound too, but usually only when singing.