Sandy Point State Park sits at the northwestern foot of the Chesapeake Bay Bridge. It was nearly deserted on a clear, cold morning last January when we arrived to view some of the area’s bountiful winter bird life. We weren’t disappointed.

At our first stop, we set up the spotting scope to scan the open Bay waters for waterfowl. Thirty yards offshore, a dozen black (male) and brown (female) ducks bobbed in the gently rolling waters. I focused the scope on a black one first, but it immediately dove underwater. My attention shifted to another nearby male. It was compact and all black except for a butter-yellow knob at the base of its shortish black bill. There was no mistaking what it was: a black scoter (Melanitta americana).

The second bird quickly dropped out of sight. These birds were actively feeding. Although the flock was composed primarily of males, a trio of females was included. They are brownish overall with pale cheeks and a clearly defined dark cap. No tell-tale yellow bulb on the bill, though.

In flight, black scoters show a very dark wing lining with silvery pale gray outer feathers. They appear plump, almost pot-bellied, as they furiously flap by.

This small raft was typical of black scoters in the Chesapeake. They tend to keep to themselves, not joining the big mixed flocks of waterfowl that are common in the winter.

Black scoters start to arrive in the Chesapeake region in mid-October, but the biggest groups show up a bit later. They’ll stay until late March.

There are three scoters that inhabit the Chesapeake Bay waters: white-winged, surf, and black. Although their plumages vary, these similarly shaped sea ducks are all diving ducks.

Only a few nests of this little-studied bird have been analyzed. The nests appear to consist of a hollow in the ground, lined with grass and down. The nests rest atop grassy areas near small ponds and lakes.

Scoters are born with full feathers and an impressive appetite. As soon as the natal feathers dry, these chicks are busy eating insects. Within minutes, they will be diving underwater for their dinners.

Because of their diet, the birds are looking for rocky bottoms where the substrate is home to aquatic invertebrates.

Black scoters are excellent divers. The birds we were watching were most likely feeding on clams in water that was probably more than 30 feet deep. They also take mussels, razor clams, scallops, the occasional semi-submerged crab and even a small amount of Bay grasses.

There are two populations of black scoter in North America.

Most of the Atlantic population winters in New England waters, but small groups will spread out sporadically all the way down to northern Florida and the upper Gulf Coast. They breed in the tundra of northern Quebec. In the West, black scoters primarily inhabit the Pacific coastal waters down through Washington. But as is the case with their Atlantic relatives, small flocks will continue well down the coast, including Baja, Mexico. They breed in the arctic tundra of northern and western Alaska.

The black scoter has a cousin in Europe. Known as the common scoter (Melanitta nigra), it appears to be descended from the same ancestral species. They have become geographically isolated for so long that they are considered a separate species. A remote Russian arctic bay appears to have some overlap between the black and common, but it is not known for sure if they interbreed…just one of the many questions that scientists have about this enigmatic waterfowl.

Over the smooth waters of the Chesapeake, we could hear the plaintive whistles of the males. The ethereal tones seemed a perfect match for this little-understood visitor from the north.

A slight wind was stirring and we were beginning to feel the cold standing by the open waters. Although most people know Sandy Point because of its inviting beaches and picnic areas in the summer, the park covers 800 acres. Heading inland a bit would get us out of the wind without diminishing our bird watching.

In addition to the open Bay, habitats here include jetties, sandy and rocky beaches, a marina, meadows, fields, marshes, ponds and an extensive forested tract.

More habitat means more birds. In fact, the park has hosted more avian species than any other Maryland location: 294!

We folded up the spotting scope and headed ashore for a little more warmth, hopeful that we would see a lot more birds.

Out on the Bay, the black scoters continued to dive and call. As they disappeared into the inky waters, I thought about how these mysterious birds continued to hide most of their secrets. Like the beckoning environs behind us, they hold avian wonders still to be discovered.