Budgerigars are dimorphic because the males' ceres turn bright blue upon maturity, while the females' ceres turn tan. The female budgies' ceres also appear wrinkled, to a greater extent during periods of fertility.
Immature budgies have pale pinkish ceres which are smooth and shiny.
The nares are set within the cere.
External links: Photo of a male budgie's cere
