At least three Great Blue Heron nests can be seen from the so-called
Columbia Waterfront.  These presumably are the ones being seen from rts. 29
and 175.  If you park in one of the lots along Little Patuxent River Parkway
to access restaurants such as Copeland's, Tomato Palace, or Clyde's, proceed
to the water.  When you hit it, turn left, follow path.  The three nests
will soon be  evident on the far shore, in a sycamore.  They presumably are
the birds displaced when the tree that they used to nest on the island fell
in a storm.  There is a heronry further north, at Vantage Point, at the far
north end of the lake, but I've been unable to actually find it all these
years.  The ones visible from the Columbia water front, however, seem to be
quite habituated to people, and appear to regard us folks on the far shore
as not threat.  Give it a few weeks, the chicks are quite amusing to watch
before they actually fledge.

Kurt Schwarz
Ellicott City
goawaybird <at> comcast <dot> net