As I was packing for an international trip recently, I received a text from the Maryland rare bird alert that almost made me drop my pre-travel plans. At Assateague Island, on the other side of the state, a Wilson’s Plover had just been seen and a short time later a second bird appeared to be in the same vicinity. Unfortunately for me, neither bird was not at a particularly accessible location and neither stuck around long anyway. On the other hand, I may not have to wait much longer before again having a chance to add this species to my state list.
Wilson’s Plovers are one of those rare but somewhat expected species for us in Maryland, and the same can be said for other parts of the mid-Atlantic and even the northeast as a whole. It breeds fairly close by and while the most recent surveys have failed to turn up concrete evidence of nesting in Maryland, it has been assumed that it will only be a matter of time before birds wander up from Virginia or North Carolina and settle down somewhere on the barrier islands to the north—indeed it is certainly possible they may already have done this. Wilson’s Plovers are small and inconspicuous and the coastal islands of Maryland (and Delaware, for that matter) are not always easy to access.
All that being said, records are sparse; it is certainly not an annual species in Maryland and some years records are lacking from the mid-Atlantic and northeast altogether. A quick perusal of eBird data will show that, in the past, this species has been relatively unlikely to produce multiple far flung records in a year. That may be starting to change, however. While last year, Wilson’s Plovers were wholly absent north of Accomack County in Virginia during the months of May and June, in 2017 several states to the north produced sightings and there have already been records from Rhode Island and New Jersey this year, in addition to the check-in from Maryland.
So what’s going on here? Well, it’s possible that this is just an example of a species that it prone to periodic vagrancy, overshooting favored nesting grounds and landing on beaches to the north. But it could also be that the increasing frequency with which multiple birds appear to be ending up far beyond their normal range is indicating a range expansion, albeit a modest one. One other interesting factor to consider here is that so many coastal species appear to be doing so poorly—in Maryland and Delaware typically southern beach-nesters like Gull-billed and Sandwich terns have never really become established, despite producing nesting attempts many years and despite a prominent presence during both their pre- and post-breeding movements. Even species with what we may think of as a firmer foothold have struggled recently. The question then becomes whether the volatility of coastal habitats, especially in an increasingly warm and increasingly storm-prone region, will work against the arrival and detection of new colonizers from the south. For my part, I’m rooting for another wave of Wilson’s Plovers, but until then, I’ll enjoy my commoner coastal arrivals.