We live in south east Virginia.  We have just noticed waterfowl that swim much lower in the water, so that pretty much all you can see are their long necks and heads.  They dive under the water and don't come up for a while.  We also see ducks, but they sit high in the water.  Any idea what these low riders are?

thanks!

it is an American Darter or Anhingia, sometimes referred to as a snakebird.  There are four species around the tropics.  They are in  the same order as the cormorants and shags (the Suliformes) which they are similar to in habits, and to the gannets, boobies and frigatebirds.