Night Herons on Mystic

Went for a quick kayak last weekend, on the 19th, putting in between the two lakes and then cruising down the Mystic River.  Got to where the river starts to widen out past the Riverside Yacht Club and then turned around.  The amazing thing was the number of Black-crowned Night Herons where I've never seen them before.  They were really thick, about one every 50 feet all along both banks.  One guy who was watching them told me that they only show up along the Mystic in June.