There was a large black blob floating on the surface. It looked like a mass of seaweed that had likely become detached during a particularly high tide. But it was particularly large. The water was incredibly still on a characteristically foggy fall day and then suddenly erupted into loud clapping and splashing. What looked like an indistinguishable dark blob on the water was actually a raft of ducks.

At this time of year, it is common to see large numbers of birds flying overhead as they migrate to warmer climates. Geese are the most obvious of the bunch with their large size, loud honking and copious droppings. Their tell-tale V shape often stands out against an otherwise gray sky. Other common flocking birds include starlings, which gather in extensive numbers called murmurations — a natural phenomenon I wrote about a couple of months ago. Sometimes these gatherings are for more efficient flight during long-distance travel, and sometimes they are for feeding together or avoiding predators. Sea birds gather in flocks as well, sometimes in the sky like a group of gulls circling overhead but more often in the water like the raft of ducks I recently saw.

I could tell from a distance that they weren’t eiders, the biggest of the sea ducks and easily identifiable by the males’ white wing patch. Their smaller size and consistent coloring meant that they were probably scoters. Scoters are chunky little ducks that bob up and down on the water with their tail feathers sticking up in back. They are one of those hearty Maine sea duck species that stay around through winter. Some migrate farther south, but many of them overwinter here and are often seen in large groups along the shore. They gather in groups for many of the same reasons that birds do in the sky: for protection, for feeding, and efficiency and direction of movement. But on the water, they also gather for social purposes. When they aren’t in breeding season, scoters, like many birds, are looking for a mate. When they gather in groups, they are assessing their options.

While the scoters I saw were in a kind of amoeba-like formation, they apparently sometimes take more shapely forms like swimming in a line, much like they also do in flight, or even gathering in a circle. It isn’t clear why they would take on the circular formation, but it could be that they do this to corral the fish that they feed on. This is much like the local pogey (or menhaden) boats that set a purse seine (a circular net that can be drawn up like a purse) around a school of fish. It’s a clever way to gather large numbers of fish.

Maybe I’ll have a chance to see this circular formation, as these scoters are likely to be here through the winter, unlike some of the shorebirds that migrate farther south. Some of their migrations are the most athletic feats imaginable. Birds as tiny as plovers can fly up to 3,000 miles without stopping. Maine has lots of different shorebirds from sandpipers to plovers to turnstones and dowitchers that breed way up north and stop through Maine over the summer before continuing on their way as far south as South America. While it is common to see little groups of shorebirds running back and forth with the waves on the beaches in the summer, when they migrate, they often fly alone. Perhaps that’s all the more reason why it is so neat to see a big, floating, gregarious group of scoters sticking together, ready for winter. They are a testament to the hearty character of Maine’s coastal life.