Great Blue Heron over Batiquitos Lagoon from www.oceanlight.com

We’re close to Batiquitos Lagoon where great blue herona and great egrets inhabit.  Unfortunately a couple of these huge beautiful bird has discovered our koi pond and found that they have enough room to land and take off.  I seen them several times on the wall that surrounds the pond and today my wife opened the front door to discover a blue heron on the bridge over the pond.  The koi are spooked and they hide underneath the deck throughout the daytime.

Not sure what to do while still maintaining the aesthetics – couple of things I read about:

– a fishing line across the pond – I can put a single line between the walls enclosing the pond, which would limit enough of the room required to land and take off.  But it may harm the bird if he doesn’t see the line on landing – which I don’t want, especially since its a protected bird.

– fishing line stretched around the perimeter of the pond.  Herons will land on ground first and then walk into the pond, so the theory is that the fishing line will startle heron and it will fly off.  I’ve read mixed reviews about this.

– A heron decoy that you move around regularly will in theory prevent heron visits since they honor each others territory.  But I also read comments that this may instead reassure the heron that there is a good meal to be had here.

– Floating alligator head or floating hippo head

– The most promising may be a sprinkler like device with motion sensor when triggered shoots out water to scare the heron away.  Unfortunately it requires a hose to be connected to it. Someone posted theirs in action:

A smaller stand-alone version intended for pets is available and requires no hose but it only emits a burst of air and a warning sound.