It's a scene right out of the Pleistocene: A gyre of thousands of white-fronted geese and snow geese, spiraling down to a field of stubble from a sky filled with purple and black cumulus. The sun is setting behind the western mountains, and the last shafts of light are incandescing the birds' pinions, making them flash like pink semaphores.
The air almost solidifies with the gabbling and yelps from 20,000 avian throats. It is not a wall of sound: It is an El Capitan of sound, a Gibraltar of sound. It would be a little threatening if not for the fact that the calls are easily recognized as exuberance, as excitement, as raucous welcome. The geese are happy to congregate, pleased to be settling down together for the night.
It is a stunning spectacle, but it is by no means a rare one - not at this time of year, not in the Sacramento Valley. The refuges, duck clubs, flooded rice fields and riparian woodlands of the Central Valley are the winter destination for the millions of migrating waterfowl - and shorebirds, raptors and songbirds - that ply the Pacific Flyway, one of the four routes used by the continent's birds during their spring and autumn migrations.
You don't have to be an avid birder to be thrilled by the winter aggregations of geese, ducks and shorebirds in the Sacramento Valley - or along Tomales or Richardson bays, or the alkali lakes of northeastern California. You simply have to be human, and demonstrate moderate sensitivity to the extreme beauty and power that nature can manifest.
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/11/18/CM70T3FCJ.DTL