The Connecticut Department of Energy and Environmental Protection website lists out some very important and educational information concerning the Piping Plover here, and here is a good passage concerning behavior:
Interesting Facts: When humans or enemies come too close to a plover nest, the adults will try to distract them by flapping around like a wounded bird. This is sometimes referred to as a "broken wing" display. Plovers have a defined beachfront territory. Beachgoers are met at the beginning of the territory by the plover and escorted along by the walking bird until the territory ends. Unlike their nesting neighbors, the least terns, that fly and dive at enemies, adult plovers walk and stop, walk and stop to avoid detection by visually blending into the background.
As well as...
What You Can Do: Respect all plover nesting areas that are fenced or posted for the birds' protection. Do not approach or linger near piping plovers or their nests. If pets are permitted on beaches used by plovers, keep pets on a leash. Keep housecats in the house, especially at night, during the nesting season. Don't leave or bury trash or food scraps on beaches. Garbage attracts predators which may prey upon piping plover eggs and chicks.
If anyone ever sees a Piping Plover doing the "broken wing" display they should immediately stop and cautiously yet quickly exit the area. Here is a photo of such a display taken quickly for educational purposes while working on an exclosure - this is not something we want to see.
The same goes for overly excited or agitated birds, those with young in tow or nearby, and any making loud rapid alarm calls. Piping Plover adults can also shake and wiggle, attempting to draw you away in hopes that you will follow them away from the nest or young, or crouch down in the sand. You should not even regularly encounter birds following you in the quoted manner described above if you are maintaining a safe distance.
We want to monitor the birds, not survey them thoroughly at all costs, and even staff is instructed to keep their distance at the expense of data and information in order to better protect the birds and their eggs or young. Here is a fantastic illustration of where you should walk on the beach whenever possible in order to prevent any disruptions or incidents.
For the most part the wet sand is always a safe zone, and even if birds are feeding in it or along it you should be able to pick them out easier and thus be able to give them more room, or allow them space to retreat easily back into the higher sand and dunes. Thanks to Bird Studies Canada/Environment Canada for that, and to all of you for your constant efforts. They are unbelievably and unequivocally appreciated.