I have a small flock of geese and they are totally alert to any form of danger that might exist around them. They never miss a trick, even when you want them to. Geese tend to bully smaller birds, though normally not in a mean way, so when you are trying to feed all the birds at once, the geese usually get the King’s share of the goodies. But when there is danger about, such as predatory birds, weasels, opossums, dogs, raccoons, and big cats, the geese make excellent watch dogs.
This is a service they perform willingly, and with class and grace. They know they are the biggest birds in the flock so they take a natural responsibility for the others. When danger appears, the geese spread their wings, honk loudly and repeatedly in warning, and stomp toward the direction of safety, herding the rest of the flock in front of them. This is how humans herd ducks, with arms outspread like a set of wings, and it works like a charm. The smaller birds and the geese all respect that gesture.
Geese are quite capable of taking care of a flock of fowl, both water and land fowl, due to the fact that their serrated bills are nasty when used to full extent. I have personally witnessed what damage a goose can do with that bill, they can bite clear through a galvanized metal bucket. But these same geese are gentle as lambs when you feed them from your hand. They know exactly how hard they can bite before you will feel pain. Generally speaking, when an angry goose bites you, you will have an instant bruise or blood blister, but they seldom break the skin. They certainly could if they wanted to, but they are not viscious with their human keepers.
Geese are demanding, especially the "mouthy" breeds, like the Chinese. They squeal, scream, bark, make a sound like an air-horn, and just basically raise the roof with their "chatting". Amid a flock of geese you cannot hear yourself think, but to get them to shut up is fairly simple…you just raise your "wings" again and scream louder than they do. The former is easy enough, but you have to be pretty loud to be heard above a goose, and even if you are, they will typically only shut up for the barest of seconds. Geese like to be heard and do not take any lip from anyone else, humans included.
I have one female White Chinese goose who makes a sound similar to "what!" If you say "what" to her, she will bark it right back at you, over and over again. This sport seems to distress her mate, who will try to come to her protection. We have a Brown Chinese goose who says, "hoink" instead of "honk". So, certain sounds seem to be characteristic of a breed while others apparently are simply characteristic of the individual. Geese are graceful birds, though a little clumsy on their feet. They tend to walk about with their eyes on the sky, probably alert to danger, so they miss the little details like the tree they are about to walk into.
I have seen geese trip over water buckets, a hole in the ground, other smaller birds, anything that gets in their paths, simply because they seldom look where they are going. This seems to be more of a problem with the "swan-like" geese, because they have very long necks and long legs and the ground just seems to be a nuisance to them, since they would rather be watching the sky. Most of the bigger geese have wingspans that stretch up to about five feet long, and I imagine they do look rather intimidating to the predatory animals and birds that stop by to visit.
So, if you have a flock of ducks, chickens, pheasants, pea-fowl, or whatever, the addition of at least a pair of geese would probably be a good idea. They are strong, loud, overbearing, gentle and alert, just the qualities you need in a good watch dog.