Local officials call the geese a nuisance, saying their droppings are causing health and safety problems.
The county has rounded up hundreds of geese and killed them in portable gas chambers, angering animal lovers.
“It’s genocide of a wild species,” said Sue Russell with Center for Animal Protection.
New Jersey animal rights activists say there are non-lethal means of separating geese and people, such as using dogs to chase them away.
They charge that Union County chose gassing because it was fast and easy. “It’s a horrific way to die for a human or a bird, especially birds as sensitive as Canada geese,” said Russell.
Some New Jersey residents agree. Goose lover Hana Sedlackova says the community has been shattered by the gassings.
“It’s like losing a pet, a member of the family really. It’s brutal,” she told CBC News.
The gassings have fuelled a movement that’s pressuring some states to find ways to allow the geese to live in the community. But so far it’s met without much success. Gassing remains a popular method of goose control in a number of places.
Hundreds of thousands, perhaps millions of Canada geese have crossed the border and have now claimed the United States as their home.