The grey Heron is native to most of Europe, Asia and even parts of Norther Africa, however during the summer months they can be seen as far north as the Norwegan coast and the Arctic circle. They're very common wadding birds and most of you will have seen them around if you've been to lakes or marsh land.
They stand at about a meter tall so they're easily spotted. they have a wing span of almost 2 meters. They're easy to identify when flying as they have a slow flapping motion unlike other large birds that tend to glide. You can also see their long neck is curled back in a sort of "S" shape.
For the most part they live on fish and frogs, caught out of the water with their long bill. However they will sometimes take small mammals, reptiles, and ducklings.
Sometimes people tell you to put a plastic heron next to your pond to discourage real herons from eating your fish, but to be honest it doesn't really work and neither does putting netting over your pond. My best advice would be not to keep fish in your pond at all!!