ON THE UPPER ST. CROIX RIVER - Perfect as perfect can be, last Wednesday unfolded beautifully, the four of us in two canoes, drifting downstream, dipping our paddles minimally into this clear river to adjust course. As we traveled we cast fly lines toward fishy-looking haunts. But the effort seemed secondary to our broader immersion in late summer breezes and emerald shorelines, lazing on this very cool river beneath scudding clouds.

So it goes in August in Minnesota and Wisconsin, as anglers often switch from lake fishing to river fishing. Species sought transition as well. Walleyes were the big deal in lakes in May, June and July. Now as summer progresses gracefully toward a regretful ending, smallmouth bass in moving water are primary targets.

With me were Bob Nasby, his grandson, Bobby McGraw, both of the Twin Cities, and Rob Kolakowski of River Falls, Wis.

It's a trip we've made many times, and one open to anyone with a day or even less to spare. Wild River Outfitters in Grantsburg, Wis., makes the outing easy by shuttling paddlers and their gear, including canoes, upriver to be dropped off at a landing of their choice.

From there it's all downstream.

We were looking for surface action, fishing the top. A smallie catapulting from unknown depths, breaking a river's surface to gobble a popper or other top-water bait, is akin to seeing a shooting star on a black night over and over, a rush that sears the memory.

We weren't far downstream when Rob, in the bow of my canoe, hooked up with the day's first fish. This wasn't a big bass; those would come in their own time, this day or another. Still it was a fish, and it swept a broad bend into Rob's 9-foot graphite wand.

As are Bob and Bobby, Rob is a champion fly caster, and after he released the smallie he quickly unfurled more tight loops of brightly colored line over the shimmering St. Croix.

If you're insecure at all about your abilities with a fly rod, this isn't the trio to fish with. From my perch the three cast as if they were figures in a painting coming to life in slow motion, their throws occurring in smooth succession.

Doubling up like this in canoes, fly anglers must not cast at cross-purposes, fouling their lines. Instead, stern fishermen must throw alternately with bowmen, until their timed motions, like fly casting itself, becomes automatic, and everyone fishes on down the river.

Bob hooked the next fish, a smallmouth perhaps not quite "with shoulders," but a proud specimen nonetheless.

Quickly his forward angler and faithful grandson reeled in his line to better witness this ancient struggle, man vs. fish. A foregone conclusion here that man would win. The focus instead was on the smallmouth, wondering if he (or she) would tail-walk once or twice, or perhaps leap into the air altogether, leaving the water as if shocked, like no walleye ever could.

Only in anglers' dreams do rivers hold fish uniformly. So on this day we pocket-fished, looking for shadowy overhangs that provided cover, sometimes only tiny niches of these we suspected might hide the quarry we sought.

Other times it was smooth, quiet water behind boulders we cast to, visualizing as we did the possibility that a fish was holding in the seam between fast water and slow, anticipating morsels flowing by, carried by the current. Like people, fish are lazy. But a fish's sloth is excusable: The conservation of energy in pursuit of more energy is the sharp knife blade on which their survival is precariously balanced.

At midday, we beached our canoes. We had sandwiches and drinks in coolers, and stretching our legs felt good. There were fish to be caught. But already we knew our productivity on this day would be middling. Blame it on the north wind that blew recently. Or whatever. Anyway, we had far from given up: We might yet tie into a northern pike or muskie, regardless the apparent reluctance of smallmouths to cooperate.

"Bagatelle," Bob said.

I had asked the name of the restaurant in Key West where he and I and Dick Hanousek ate after long days fishing for tarpon off the Marquesas.

This was in the early 1980s and one day Bob landed a massive tarpon on a fly on the day's last drift. Afterward the food and drink were good and we ate on a balcony overlooking Duval Street, caught up in Caribbean breezes, a real carnival.

But was it better than this, on the St. Croix, so many years later?

Pushing off from lunch, we soon were swept downstream, the river clear from top to bottom, where its sand, rocks and open shells were easily seen.

Highlight of the afternoon was a northern pike Bobby landed on a popper. No tarpon but a good fish nonetheless, and the celebration thereafter suffered not a whit by comparison to the one long ago in Florida.

Near our takeout, a half-dozen teenagers splashed in the river. They were from Grantsburg and this was their recreation, proof again that rivers dole out their favors indiscriminately.

Pulling our canoes to shore, we were happy to have caught some fish.

And to have spent the day again in moving water, just like the kids who swam nearby.