Canada geese are protected under the Migratory Bird Treaty Act. That is the starting condition for anyone working with this species, and it rules out most of what a frustrated property owner is tempted to try first.
New York DEC states that no federal or state permit is needed to scare, herd or chase geese with dogs or noisemakers, provided the birds are not physically harmed. Read that sentence carefully, because the whole method sits inside it. The legality of what we do depends on the birds being unharmed. It is not a value we bolted on afterwards, it is the condition that makes the work lawful at all, and the moment a program crossed that line it would become a legally different activity.
The method itself is older than the company. A Border Collie works a stalking posture, head low and shoulders down, moving in a controlled arc. To a goose that reads as a predator, and the response is instinctive rather than trained out of the bird. MassWildlife's own guidance names trained dogs as especially effective among the non-lethal options available, which is a state wildlife agency describing this as an established management category rather than a novelty.
The handler matters as much as the dog. The dog stays under control, makes no contact, and is called off before pressure turns into pursuit. On water, the dogs will go in and work birds off the surface. Nothing in that sequence requires harming a goose and nothing about it is improvised on the day.