Heron in the morning

Herons are usually seen in singular.  I recently counted 10, yes 10, fly over me in straight line formation (well, a little squiggly) and high up.  The squawk is unmistakable, the shape and wing flap as well.  I have seen four or five together before this sighting.
This morning I shot this photo of a single blue on a perch along my pier.  Once disturbed, three blues went a flying.  The others were out of my sight.

Perhaps they roosted for the night.  They are a winter regular here, so pretty when spotted on the causeway perfectly camouflaged against the marsh grass.