I published a prediction on this beach taking for plovers three years ago. It was obvious. Snowy plovers nest from Washington to Mexico. The theory goes that if they are scarce in one place that they are "locally endangered." There is no support for this in the ESA.
For the FWS to list a local population, they must have designated it to be an Evolutionarily Significant Unit. That means that they are genetically distinct, isolated, and significant to species survival; it can't be just one of those; it has to be all three. Of course, the definition of what is "significant to species survival" is entirely up to the local bureaucrats and their dependent scientists. Anyone who would have a contrary opinion and supporting data is usually systematically frozen out of the process.
Yep, I remember that part, pretty predictable aren't they?