Interesting article in the San Francisco Chronicle today about how crews removing sand from the roads and pedestrian paths adjacent to the city's Ocean Beach must perfectly time their work according to the breeding habits of Western Snowy Plovers, an endangered species. Apparently, the bird leaves Ocean Beach for Half Moon Bay and other spots to breed, giving workers a one- or two-month window to bring in heavy equipment and move sand around. Once the plover are back, all work stops again.