That might not be such an off-the-wall theory. If the wind is in a favorable direction for migration, the birds will take advantage of it. The white-throated sparrows moved through here in record time this year because of the favorable winds. And if the wind is not blowing in a favorable direction, the birds stay low to keep out of it while they're foraging. So they can be pretty dang hard to see
We do live in the area cut off by a fork in the migratory pathway--between those birds following the Mississippi and its tributaries (and eventually coming up the Chippewa and its tributaries to get here) and the bird migrating further east and using the great lakes as a path. There is a little wetland to the south of us which empties into the south fork of the Eau Claire river, as well. Plus a lot of the birds breed in the surrounding forest. So we're well-situated to see birds.