AT THE OLD CABIN in the Church O The Pines by the Mississippi, an April breeze tosses the pine tops. But not enough to deter an eager paddler from slipping the Bluebird II into the water, for the first Spring outing. It was a long, hard winter in Minnesota. And it is always a thrill to feel the first pull of the paddle, to watch the first ripples glide away. To scan the waters and shorelines for the first harbingers. Of Spring, that is. Of course, putting a canoe in the water is a pretty fine harbinger, itself.