But being short on military, they send only owls...
An extreme decline in the rodent population in the boreal forest has caused thousands of owls to head south in search of food.
More than 2,000 great gray owls, 200 hawk owls and 300 boreal owls have been spotted in Minnesota, northern Michigan and other parts of the upper US. More typical numbers would be last year's: 35 great gray owls, 6 northern hawk owls and 1 boreal owl.
This massive bird migration is called an "irruption", and apparently an irruption of this proportion is extremely rare.
OK, this qualifies as my most off-topic post ever. The connection to Canada, though real, was just an excuse to post photos of these amazing birds. I love birds of prey, and these faces are magnificent. The maps (which you probably can't see well here) are their territories.
Click here and then on "follow the rats" (on the right) for larger pictures.