In the US, it's usually Mexicans (or Central Americans) leaving trash piles everywhere they go. You'll see Mexicans taking their huge extended families to a picnic at a city park, and then leaving it to look like the city dump despite the fact that there's a trash can only 10 yards away from the area they were infesting. Nobody, not even blacks, can compete with the Mexican propensity to trash every public space (not to mention their own yards).
I think it has something to do with the difference between the countries that were originally British colonies and those that were Spanish colonies. You find the same thing in Asia; just look at the difference between urban public spaces in the Philippines and those in Hong Kong or Singapore.
You haven’t been on an indigenous reservation!