Climate Central: As the birdwatchers of Arrowhead Marsh strain through binoculars for glimpses of California clapper rails, they could easily miss the warning signs of an obscure threat to the species' survival.
Grassy banks at the heart of the marsh are sloughing at the edges. With a spike in sea levels looming, chunks of mud are already dissolving into the tidal waterway, shrinking one of the few remaining homes of a species that once nested throughout the marshes that ringed San Francisco Bay's sweeping watershed....