With the Avalon Seawatch left as the only CMBO/ NJ Audubon migration count still running, here's a series of photos of waterbird flocks in flight - practice at home or whet your appetite for some great late season seawatching on the Jersey shore.
Tundra Swans seem to be putting in a strong showing in Cape May this fall - most days with north or west winds, small groups have been passing over giving their wild whooping calls. ID is relatively straightforward - though Mute Swans are quite common here, as a general rule they don't fly high overhead in large flocks. If you want more of a concrete field mark, check out the relative proportions - Tundra Swans are compact with thin necks and short tails (feet usually project beyond the tail tip in flight).
Ring-necked Ducks are relatively common diving ducks on freshwater ponds and lakes in New Jersey, but they also pass by the coast as migrants and can occasionally be seen in numbers during a seawatch. Medium contrast wings set into a constant fast whirring motion on a duck with a dark back = Ring-necked Duck.
Canada Geese are common migrants throughout the region and are a good baseline for comparing other less frequently observed migrants. After you know you are looking at Canada Geese, keep watching them far into the distance and ask yourself if you still know what the birds are - one good separation point from cormorants, other large dark waterbirds that fly in large flocks, is that geese typically don't glide in migrant flight, unlike cormorants, which typically intersperse flapping flight with lots of short glides.
Wood Ducks usually move in fast, twisting flocks in almost teal-like fashion. Shape is really useful in identifying these beauties in flight: Wood Ducks have long tails that appear blunt.
Of course, if you are seawatching on the Jersey shore in autumn, you are going to run into scoters before too much time has passed. This flock of Surf Scoters actually flew high overland, but scoters are typically seen in long echelons fairly close to the ocean, where their overall dark coloration and extremely angular wings on hefty, muscular bodies help separate them from other waterbirds.