How can I tell if my cockatiel is male or female?

I've had Sunny for a few months and I'm dying to know if she's actually a she! She's a normal grey cockatiel. How do you sex a cockatiel — is it the cheek patches, behaviour, or do I need a DNA test?

For normal greys: adult males usually get brighter yellow faces and bright orange cheeks, females stay duller with barring under the tail. But it only shows after the first moult (~6–9 months), and many mutations (lutino, pied, etc.) can't be visually sexed at all.

Great question — cockatiel sexing has a few methods, with different reliability:

• Visual (normal greys only): after the first moult (~6–9 months), males develop a bright yellow face and vivid orange cheeks; females keep duller colouring and often show barring/spots under the tail and wings.
• Behavioural clues: males more often whistle, mimic, and do a 'heart-shaped wings' display; females tend to be quieter — but this is just a hint, not proof.
• Colour mutations (lutino, pied, pearl, whiteface): frequently can't be visually sexed at all.
• DNA testing: an inexpensive, definitive option using a feather or nail-clip sample — the only way to be 100% sure.

If Sunny is a normal grey and past her first moult, watch the cheek/face brightness. Otherwise a DNA test settles it. See the complete cockatiel care guide for more.

Behaviour helps too — males tend to whistle, mimic, and do the 'heart wings' display; females are usually quieter. But it's not reliable. For certainty, a cheap DNA test from a feather/blood sample is the only sure way.