Readers who frequent the beach will surely have noticed a phenomenon no less a sign of spring than forsythia blooms: the sudden appearance of orange fencing and “closed area” signs. That’s right, the piping plovers are back. Efforts to protect the migratory shorebirds, on the federal list of threatened species since 1986, were the subject of a Globe Magazine cover story in August 2011. Some communities spend tens of thousands of dollars on the task, including shutting down entire beaches. “For some of the frustrated people who’d like to enjoy those beaches, too, the inconvenience has come to represent environmental do-gooding run amok,” reporter Kris Frieswick wrote. “The plovers’ defenders, though, think differently.” That latter group just received some good news, with a report released in April showing the Massachusetts plover population had increased from 591 pairs in 2010 to 656 pairs in 2011. Less good news, however, was that the 757 chicks fledged in 2011 represented a slight decline in productivity from the previous year. In short: The fight, and perhaps annoyance, continues. To read “The Curious Case of the Piping Plover,” click here.