The short answer is the market, but that doesn't say anything. It says it all, but it doesn't say anything.
Currencies are the most difficult thing to predict, particularly in the short term. Flip a coin; I have no clue. The Canadian dollar could go to $1.05, and it could go to 92ยข U.S. We are perceived as being part of the dollar bloc, so we tend to move along with the U.S. dollar. We've seen some very strange movements in currencies over the past six months at least.
As far as who is responsible, I throw my hands up. In fact, one of the biggest risks we now face is that there appears to be a bit of a currency war developing. We've seen the Japanese try to bring down their currency. We see the Chinese trying to resist bringing up their currency. We see the Americans not being too displeased with a lower currency. The Europeans don't know what they want with their currency. So the risk here is that we'll engage in comparative devaluations.