In the past week, I've seen a single Black-crowned Night Heron on the
island in Lake Whetstone which is along Montgomery Village Avenue
in Gaithersburg, MD.  I haven't seen a nest yet, tho' they have  
nested on
the island in past years.  The bird was there yesterday (Tuesday), on
Monday, and the previous Thursday (the 12th).

There are nine Great Blue Heron nests on the island as well ...

Franz Hespenheide
Gaithersburg, MD