The piping plover nest in a parking lot that had some beachgoers grumbling over the weekend is empty. A section of the lot at Roger Wheeler State Beach in Narragansett was cordoned off over the weekend to allow the nest of the endangered birds to be undisturbed. Two adult plovers and their three chicks waddled from the nest toward the beach on Monday through a makeshift path that was constructed by the U.S. Fish and Wildlife Service and the state Department of Environmental Management. That section of parking lot will remain closed today.