The NDP does more poorly in Northern Ontario cities as well (compared to rural areas), so maybe that has something to do with it.
Then, rural areas are more-left wing than urban areas?
Strange. The only place where I know this pattern is Southern France. Cities voted for the right, while rural areas were left-wing strongholds.
Hashemite, could the same reasons could explain Northern Ontario?
It's not as uncommon as one might think; it's the case in Sweden (the rural north votes for the left, whereas Stockholm votes for the right) and in many third world countries (for instance, Bangladesh). One might surmise that the rural electorate is more volatile than the urban one, because it is more homogeneous.