It was a dark and stormy night. As I looked at the next day’s forecast, Saturday didn’t look much better for Penobscot Valley Audubon’s annual boat trip to find harlequin ducks and other seabirds around Isle au Haut. As it turned out, we needn’t have worried. Offshore forecasts indicated six-foot seas overnight, and a small craft warning seemed likely. But the worst of the weather passed through early. By our scheduled 10 a.m. departure on the I…