Sunil
Before I started to work on my pond it was encircled by cat tails from the shore to 4 feet of depth, so the herons weren't able to 'wade'. They landed on standing deadwood around the pond (old trees that had died from having their roots saturated or buried from dam construction) When the heron saw a fish they dove into the water and came out with a mouthfull. The biggest I've seen them catch was a 6 to 7" fish. I've since removed the standing deadwood and eliminated their ability to pearch in the trees. Now that I've removed all of the cat tails and have my shallows back, I have the herons back as well. They just slowly stalk about in the shallow waters and I have seen them grab a fish, again medium sized, but that happens much less due to the increased structure I've added. I really have no clue as to the ratio of cover to pond surface area required for optimum results reguarding cover areas, any input about the proper ratios would be helpfull. I haven't seen any comorrants around my pond either but I'm only a few miles from the upper Delaware river and I've seen them there.