
As the sun angled down behind the west ridge, the sky turned a deeper blue, setting the stage for the ringed bill gulls. Hundreds of these birds have stopped off here, on their migration to Canada, coming up the Mississipi Valley, and then following the tributary rivers northward. Each evening, for some reason known only to them (but I suspect it's just for fun), they fly in great river-like, undulating flocks up our valley from the lake. When they reach the top of the main valley, they wheel to the east, so that the setting sun lights up their snow-white underparts against the purpling sky. I watched this spectacle for an hour, until the sun was almost behind the ridge.