How to Sex Sebastopol Geese

Why looks do not work

Unlike some poultry, geese show no reliable difference in plumage between the sexes. Ganders average larger and often carry a slightly longer, thicker neck, but the overlap between a large goose and a small gander is wide enough that size alone tells you nothing you can bank on.

This applies to every colour equally. A grey gander and a grey goose look the same. Anyone selling birds as sexed on appearance alone is guessing.

Vent sexing

Vent sexing is the definitive method. The bird is restrained, usually on its back or over a knee, and the vent is gently everted to expose the interior. In a gander a corkscrew-shaped organ is present. In a goose it is not.

It is easiest on day-old goslings and again on grown birds, and hardest in between. It also carries real risk of injury if done roughly. If you have never done it, have someone experienced show you rather than learning on your own birds from a written description.

Voice and behaviour

In adult birds voice is a genuinely useful supporting clue. Ganders tend toward a higher, thinner call; geese toward a lower, more resonant honk. It takes hearing both together to calibrate, and it is supporting evidence rather than proof.

Behaviour helps too, particularly in breeding season. Ganders position themselves between a perceived threat and the rest of the flock, and are markedly more assertive from late winter onward. Outside the season the difference narrows considerably.

Common Questions

How can you tell if a Sebastopol goose is male or female?

The only definitive method is vent sexing, where the vent is everted to check for the male organ. Ganders average larger with a higher, thinner call, but size and voice are supporting clues rather than proof.

Can you sex Sebastopol geese by their feathers?

No. Geese show no reliable plumage difference between the sexes, and that is true of every Sebastopol colour.

Pairing birds up? Read the breeding guide. Our adult birds are sold as matched unrelated pairs, which removes the question for anyone starting a breeding pen.