Two days ago, we visited the Minnesota Zoo. I was snapping pictures of the wild boar (Sus scrofa) in the excellent "Russia's Grizzly Coast" exhibit, when I overheard a fellow visitor saying, "It's just like someone in Poland watching Canada geese." This was followed by some chatter between other members of that group in what sure sounded like Polish - and I've lived in metro Chicago long enough to know a Slavic language when I hear one. I couldn't help but chuckle to myself when I heard this, because she was absolutely right. In both the Twin Cities and Chicago regions, Canada geese (Branta canadensis) are a nuisance. They may even qualify as vermin in some areas.
In high school gym class, we played touch football - which, as you might expect, was touch football in name only - on the practice football field, out at the furthest corner of school grounds. Whenever it was not occupied by bellowing adolescents, the field was preferred grazing area for an apparently non-migratory flock of geese. It was there that I learned the true meaning of the expression, "like crap through a goose." I doubt there was a single square yard on that field that was completely free of green-and-white turd-cylinders. By the time gym class moved indoors for the winter, my gym shirt - which got washed once a semester, whether it needed it or not - had enough green splotches on it to qualify as military-grade camouflage.
The fouling of the world by these winged crap factories doesn't end there. Oocytes of such infamous nasties as Giardia and Cryptosporidium [1, 2], as well as possible human hazards in the Heliobacter genus  are transmitted in goose crap. Consequently, feeding geese is discouraged in many places, as evidenced by the sign at left, seen on the Minneapolis riverfront a few years ago.
The important distinction here is that the nuisance geese are so-called resident geese. Resident geese don't migrate in any serious way, preferring to stay year-round in the cushy environment of suburban office park ponds and other areas with mowed lawns and easy access to water. Officially, the US Fish & Wildlife Service "... identifies 'resident Canada geese' as those that nest within the lower 48 States in the months of March, April, May, or June, and that reside within the lower 48 States in the months of April, May, June, July, and August ."Migratory geese tend to fly to sub-arctic Canada and Alaska in the summer to nest and are found in the contiguous 48 States only in the spring, summer, and fall .
Significantly, US FWS notes that "Canada geese normally return to the same breeding areas and no evidence presently exists documenting inter-breeding between Canada geese nesting within the lower 48 States and those subspecies nesting in northern Canada and Alaska ." That makes the distinction easier. Migratory geese are not the problem, and should continue to be protected under the Migratory Bird Treaty Act. Resident geese are the ones who chase children in parks and turn sidewalks into little green minefields.
Likewise, in many parts of the world, wild and feral pigs (both are really same species, Sus scrofa) can be a nuisance, particularly in areas where they are not native. For example, feral pigs are currently wreaking havoc in such diverse locations as Hawai'i and Great Smoky Mountains National Park, as their rooting causes soil erosion. Nevertheless, I was surprised to see what handsome and interesting animals the wild pigs at the zoo were. They are also BIG - they must be at least three and a half feet tall at the shoulder. No wonder medieval European hunters were afraid of them.
They're not dumb brutes, though. Pigs are smart, and they seem to be social creatures, as evidenced by the spooning swine at left. They vocalize a lot, too, especially for ungulates.
The important thing, though, is that it's all about context. If I lived somewhere where feral pigs are a nuisance, I wouldn't be at all interested in these Russian boars at the zoo; they would be just like resident Canada geese - somewhere between "uninteresting" and "vermin."
A related topic for another time: the contrast in awesomeness between the closely-related Canada goose (Branta canadensis), my opinion of which is clear from above, and the nēnē or Hawaiian goose (Branta sandvicensis), which I hold in high esteem.
 T. Graczyk, R. Fayer, J. Trout, E. Lewis, C. Farley, I. Sulaiman, A. Lal (1998). "Giardia sp. cysts and infectious Cryptosporidium parvum oocysts in the feces of migratory Canada geese (Branta canadensis)." Applied and Environmental Microbiology 64:7.
 H. Kassa, B. Harrington, M. Bisesi (2004). "Cryptosporidiosis: A brief literature review and update regarding Cryptosporidium in feces of Canada geese (Branta canadensis)." Journal of Environmental Health 66:7.
 J. Fox, N. Taylor, S. Howe, M. Tidd, S. Xu, B. Paster, F. Dewhirst (2006). "Helicobacter anseris sp. nov. and Helicobacter brantae sp. nov., isolated from feces of resident Canada geese in the greater Boston area." Applied and Environmental Microbiology 72:7.
 US Fish & Wildlife Service. "Resident Canada goose management: Questions and answers." Division of Migratory Birds report. Retrieved from http://www.fws.gov/migratorybirds/issues/cangeese/Draft_EIS/Q&A%27s2.htm on December 28, 2008.
 US Fish & Wildlife Service (2002). "Resident Canada geese populations." Division of Migratory Birds report. Retrieved from http://www.fws.gov/northeast/migratorybirds/canada_geese.pdf.