Is This Bird Supposed To Be Here?

I couldn't believe my eyes the other day. I was leaving my house and right down the street I saw this giant bird standing there. It looked like something I would see at the zoo. It was massive and it didn't look like it belonged there. I snapped a pic and sent it to my uncle who knows birds. He told me it was a Great Egret. I asked him if it was common for them to be there? He said sort of. But usually they are found in shallow waters, so it must have found a pond or something that had fish in it. Pretty crazy to see in El Cajon!