On Tuesday, Jeannette and I birded from Kittery through Ogunquit. Today, my friend Mike (an old friend from NJ who just retired and moved up here – yes, another birder “from away!”) and I birded the Wells area.

The goal of each of these two outing was terns. In addition to the breeding species - Arctic, Common, Least, and Roseate – a number of other species occur here as rarities. Last week, Maine’s coast saw an impressive incursion of rare southern terns, including the state’s 2nd record of a Bridled Tern from Outer Green Island, and the state’s 10th record of a Gull-billed Tern at Popham Beach State Park. Add to this a rare, but regular, Caspian Tern (also from Popham), a report of a Sooty Tern from Outer Green (about 15 state records, a Sandwich Tern from Stratton Island (about 15 state records), two Black Skimmers and two Royal Terns from Popham (a couple of dozen state records/reports), and you have one heckuva tern “week-list” for the state!

I saw none of them.

I was even at Popham Beach the day after the Royal and Gull-billed Terns were seen, on my field trip with the Young Birders. But, no rare terns. (Popham Beach saw a miniature “Cape May Effect.” So many good birders were visiting the park due to the ABA Convention tours there, that they were bound to find good birds! Good birders does seem to equal good birds!).

My coverage of the Southcoast was motivated in large part to find more of these terns. For one thing, I haven’t seen any of the aforementioned terns in Maine. Two, I was curious as to the extent of this tern “irruption.” Jeannette and I didn’t “tern” up anything unusual, but today, Mike and I had an adult Caspian Tern on the beach at Laudholm Beach. Sure, it was the least rare of the lot, but it was still great to see!

The big question is,” Why are these terns showing up here?” I had a good discussion with a number of birders at the Convention, as we tossed around a few hypothesis. One, this extensive southerly flow that has brought us all of this tropical moisture certainly has aided the arrival of these birds. But, is this the ultimate cause? Why aren’t these birds breeding somewhere? Has there been a massive nesting failure somewhere in the West Indies? Is there a food shortage? Is there more food than usual in the Gulf of Maine? A change in water temperature? A change in climate???

We may only be able to guess at why these southern terns have decided to spend part of their summer in Maine, but searching for answers – but usually just finding more questions – is part of the reason I go birding!