The paddlers of spring

There are certain messages that nature and the human race exchange each spring to signal that winter is over and it is safe to come out. If a crocus pushes up, vulnerable and exposed, the least we can do is take off our earmuffs and mittens, and so we oblige.

That other springtime cliche - a robin on the lawn - can shame us away from steam radiators and hot cocoa, and ought to.

Then there are the examples that pioneers of our own species act out for us. One of the rituals that says the world has survived its annual mini-ice age is boat-launching. On the Charles River, outside of Boston, the canoeists have already appeared. Mostly young, they are getting the season underway with cold splashes and loud shouts, energetically sending their craft shooting in this direction and that, like slightly frozen water bugs.

Later, when the sun bakes down and the insects begin to hum and buzz, different sorts of canoeists will appear - more passive, going with the flow. But for now, the water belongs to shivering canoeists in their guise as goose-pimple overachievers.

It is almost 120 years since one of the great canoe activists, John MacGregor , developed a little extra drama out of this springtime ritual. A vigorous Scotsman - described by his biographer as a lawyer, philanthropist, and ''controversialist'' - MacGregor, we can speculate, felt a sudden seasonal urge to throw himself into life's torrent in his 15-foot canoe, the Rob Roy. Setting a silk Union Jack firmly in place, he picked up his double-bladed paddle and for the next three months propelled himself up the Rhine, down the Danube, and all over the Moselle and Marne, not to mention Lake Constance - distributing copies of the New Testament along the way. By the time he paddled back up the Thames under Westminster Bridge, MacGregor had traveled over a thousand miles, dipping into more than 20 rivers and lakes.

Dynamic canoeing, to be sure. No wonder Napoleon III held up MacGregor as a model, recommending that all good Frenchmen put their back to the paddle. Allons , enfants!m

As spring mellows, a second sort of canoeist goes in for what Thoreau called ''fluvial excursions.'' The MacGregor school of canoeist rides the water like a spirited steed - ''gallantly as a race horse,'' as one heavy dipper phrased it. The second sort of canoeist remains purposeful, but is more relaxed about it. Like Thoreau, he or she has seen chips, weeds, even tree branches floating past and is eager to become a spring migrant too - in moderation.

MacGregor is the right stuff that the metaphor ''paddle your own canoe'' must have been derived from. With MacGregor, one waves a defiant paddle and by preference travels upstream. The second sort of canoeist may cherish a destination, but downstream will do just fine, thank you.

There is a third and even more admirably languid sort of canoeist - practically a spectator. The paddle becomes a prop, dipped in the water only now and then, mostly to produce fascinating little spiral patterns. This meanderer pays a lot of attention to clouds in the sky, gentian and goldenrod on the shore , and dragonflies. The third sort of canoeist likes still water, and cooperates to keep it that way. A semi-reclining position is favored. Solitude and silence are valued. The third sort of canoeist is a gorgeous floater.

This canoeist dreams of turning the whole world into a ''floating world'' - the universe as portrayed in a Japanese print. Detached from the rude bumpiness of life on land, the third sort of canoeist engages only in exercise of the philosophical kind.

If desired, a canoeist can play all three roles as the season progresses, going from the April competitiveness of a water-borne jogger to the July languor of a Method actor impersonating a water lily. That may be the best thing about canoeing. In style, as in every other respect, a canoeist is entitled to drift.