Sometimes the last days of Deep Winter carry a great thaw. One day I went out to the river in the warmth of such a thaw, when cumulus clouds sped across the sky in gusts of the southwest wind, and the water of the river was shining with low, brisk waves of silvers, blues and grays. The oaks of the far bank were black against the bright sky. Up the hill, patches of yellow Osage glowed like the flush of expanding spring buds. Below the trees, hardy green chickweed, wild onion, garlic mustard,