1. Size: Generally, male geese (ganders) are larger than female geese (geese) in terms of overall body size and weight.
2. Neck Length: Male geese typically have longer and thicker necks compared to females, especially during breeding season.
3. Head Shape: Ganders often have a larger, more pronounced bump on the top of their heads called the "knob" or "boss," while females have a smaller or absent knob.
4. Bill Size and Shape: Male geese usually possess larger and more robust bills compared to females, and the bill color may also vary between sexes in certain species.
5. Plumage: Male geese may have more vibrant and intricate plumage during the breeding season, displaying brighter and more distinct markings.
6. Behavior and Vocalizations: Ganders tend to be more vocal and territorial during mating season, emitting louder honking sounds and actively defending their territory.
It's worth noting that these characteristics can vary between different species of geese, and there can be some overlap in traits between males and females. For a definitive sex determination, it's recommended to consult with experienced bird experts or use genetic testing methods.