I presume this will apply to Minnesota pike since it seems to apply (almost) everywhere I've fished for "spring" pike.
The water temp is a key factor, typically, when the temp goes to 60F to 68F is when the big guys come in cruising the shallows (2 to 5 feet deep). Weed growth is the other factor in shallows, you need about 4 to 6 inches of "cover" for the bait to hide in. So bring your thermometer along and check the surface temp. Also, go cruising very slowly over the shallows you plan to fish, if the big guys are around, you will often spook them away from their lies and they leave a dust cloud on the bottom.
So check the temp, look for early weed growth and find bottom clouds and you be into big ones all day long!
Pete AKA Frenchcreek from Calgary