For where you are, a blend of winter rye (not rye grass), white/red/alsike clover, and mixed brassicas (rape,turnips,kale). I have something similar, but I doubt the crimson clover in mine will do anything that far north. http://bioplots.com/Bioplots_Throw_Pro.html

Beware of most throw and grows, most are repackaged ryegrass with very little wildlife value.