I just wanted to comment. At some point, a poster stated that the tail shape of geese and ganders are different, with one being square and the other being pointed.
Observing my own geese, I see that the Blue American ganders can pull their tails tight and they don't looked pointed, but they do have tight rounded shape. But the same ganders often relax their tail a bit and then the tails look square. Their normal look is a square tail.
All the Poms, both genders, show square tails. I haven't seen any of them pull the tail tight so that it looks pointed. Which doesn't mean that they can't.
So, in conclusion, I wouldn't rely upon the shape of the tail to determine the gender of geese.
Observing my own geese, I see that the Blue American ganders can pull their tails tight and they don't looked pointed, but they do have tight rounded shape. But the same ganders often relax their tail a bit and then the tails look square. Their normal look is a square tail.
All the Poms, both genders, show square tails. I haven't seen any of them pull the tail tight so that it looks pointed. Which doesn't mean that they can't.
So, in conclusion, I wouldn't rely upon the shape of the tail to determine the gender of geese.