[image deleted] My gosh, like they know what borders are?
They're called Canada geese because that's what how British referred to North America way back. There's a whole bunch of species with "Canadensis" (Canadian), from Amelancheir canadensis (Serviceberry) to Sambucus canadensis (American elderberry) to, yes, Branta canadensis (Canada goose) in their scientific name that are native to the continent - the North American continent, not just Canada proper.
The only place in the United States of America that Canada geese are invasive is Hawaii, and that's all the way out the Pacific, way way out. No biggie, they were ancestral to the Hawaiian goose anyways, so no major ecological disruptions going to happen there. Probably.
They're chiefly grazers, that's why they're seen on grass eating the grass that they eat when they eat that grass.
Ducks are aquatic, eating everything from aquatic plants to fish, frogs, insects, worms and whatever other critters typically found in the water. The're omnivorous. Geese are herbivorous.
