In broad daylight I was able to confirm something I'd read about the constant, loud din of their voices: relatively few birds are actually vocalizing at any one time, perhaps only one in thirty. Biologists speculate that snow geese recognize each other's voices and that family units of three or four maintain contact in these vast aggregations by calling out to one another. What sounds like mindless chaos to the human ear, then, may actually be a complex pattern of solicitous cries, discretely distinguished by snow geese.

Another sound that is easier to decipher in daylight is the rising squall that signals they are leaving the water. It's like the sustained hammering of a waterfall or a wind booming in the full crowns of large trees.

One wonders, watching the geese fly off in flocks of a hundred or a thousand, if they would be quite so arresting without their stunning whiteness. When they fly with the sun behind them, the opaque white of their bodies, the white of water-polished seashells, is set off against grayer whites in their tail feathers and in their translucent, black-tipped wings. Up close these are the dense, impeccable whites of an arctic fox. Against the grays and blues of a storm-laden sky, the whiteness has a surreal glow, a brilliance without shadow.

I remember watching a large flock rise one morning from a plowed field about a mile distant. I had been watching clouds, the soft, buoyant, wind-blown edges of immaculate cumulus. The birds rose against much darker clouds to the east. There was something vaguely ominous in this apparition, as if the earth had opened and poured them forth, like a wind, a blizzard, which unfurled across the horizon above the dark soil, becoming wider and higher in the sky than my field of vision could encompass, great swirling currents of birds in a rattling of wings, one fluid recurved sweep of 10,000 passing through the open spaces in another, counterflying flock, while beyond them lattice after lattice passed like sliding walls, until in the whole sky you lost your depth of field and felt as though you were looking up from the floor of the ocean through shoals of fish.