I haven't seen a Great Blue Heron after the fish in that pond since the a pair of Redwinged Blackbirds took up housekeeping. May be just a coincidence, but I do know they will drive off an Osprey as a pair would harass one every time it showed up at my biggest pond in the past. Osprey finally gave up in frustration.
The clump of cattails the nest is hidden in:

Zoom in of nest with eggs. Blends right in:
