There is an invisible boundary midway between Shoreline Park and the open tidal flats of San Francisco Bay beyond which the world belongs entirely to winged things: gulls and terns, innumerable songbirds, snoozing ducks and colonies of croaking pelicans, herons and egrets that stilt-walk through the grass and curl their necks into figure eights when they fly, and the large solitary raven that plucks mollusks from the oozing mud and breaks them on the rocks. There are insects too: ladybugs and drab buzzing beetles, honeybees and bumblebees, and the broad black and yellow and small white butterflies that flit like fairies through the mustard flowers and the cowbane on either side of the path.
I spent my lunch hour today hiking down the levies that escort Stevens Creek and Whisman Slough into the Bay. It’s a gravel trail on top that drops on the right into cattails and tidal ponds and on the left into lush sloping lawns that verge the creek, thick with marsh grass and hardy low shrubs, where ground squirrels scamper and jackrabbits hop incautiously from flower to flower. At low tide the place has a rich sour odor of sweating mud and rotting vegetable matter. A mile and a half out the fresh water from Stevens Creek ceases to flow eastward as it had all the way from the Santa Cruz Mountains and the saltwater from the Bay begins to push back up the half-empty channel.
Set here and there in the ponds are false islands, hunters’ blinds of sun-bleached wooden planking gapped like teeth when the gums have receded to allow for the barrels of shotguns in season. There are metal towers for power lines, too, which seem oddly out of place, and the hum of electricity running through the cables is audible at a distance. The path dead-ends at the open tidal flats, a vast killing field of saline mud where gulls in their thousands hunt the puddles for stranded fish, and clams and mussels poke up from the silt like paving tiles. A bubbly, sucking sound of water leeching from the exposed earth in every direction makes a chorus to beg back the tide, which is on its way anyhow. Meanwhile the circling raven eyes me curiously.