Backyard ponds are a place of peace and tranquility. Add fish, and your pond becomes a beautiful, relaxing sanctuary. With that beauty and tranquility comes a possible visit from the pesky crane, also known throughout the USA as a heron, to feed on your clear, clean, stocked, backyard pond. Since cranes are a protected species, killing or injuring them is not an option. But there are devices and ideas available to keep the birds away.
Cranes may enter your pond by flying, but they prefer walking in. Fishing line strung randomly 3 to 6 inches above the ground, where the heron enter, will frighten them as it trips their legs. The lines can also be connected in various locations to set off gunpowder caps or rattle noise makers like pie tins or tin cans. However, these can be unsightly unless hidden in plant vegetation. The gunpowder caps will go off once, so you'll have to use more than one.
Helium balloons are another deterrent for cranes because they act as a bird of prey circling above. Foil balloons are flashy and tend to scare the birds. Balloons should be tethered to fly 50 to 75 feet above the pond. Relocate them every four to five days. You also might consider buying a heli-kite, which is similar to a helium balloon, and has fins to help it fly above the pond. It better suits the pond environment.
Provide Fish Cover
PVC or plastic drain pipe, bricks, cinder blocks, or a "koi kastle" will give your fish a place to hide, provided your crane doesn't wait for the fish to swim out. Vegetation growing in your pond gives off valuable oxygen, and large rocks add character while providing places for your fish to hide.
Bird nets stretched over your entire pond keep the cranes from walking in. The nets keep them from flying in as well, if placed high enough. The drawback is that nets are unattractive and take away from the beauty of your backyard pond.
Scarecrows and Scare Decoys
Scarecrows or black flags that move in the wind will startle the cranes and they'll fly away. Relocate them every four to five days. Placing fake predators like snakes, alligators, or fish that jerk back when caught, do a fine job, especially if they float around and look alive. Be sure to move them if they're stationary. Upside-down mouse traps work, if chosen by the crane as food, and they snap. Vegetation planted around the pond hides real predators such as snakes and keeps the crane frightened. An owl perched pond-side works too, but change the location every four to five days.
Deeper Pond Water
Cranes don't like wading or stepping into deep water. Ponds with a foot or more drop-off to waterline, and pond water deeper than a foot, should keep the cranes away. Of course, it is best to do this in the construction stage of the pond.
The dog is another device, especially if it chases birds away. Even the littlest dog will bark and make enough noise to scare the crane. On a chain close to the pond, or running loose, the dog works best.