They just showed up in our front yard last year. Our backyard and pool was being remodeled at the time so they didn't go back there much but now they fly back there, sometimes early in the morning, but mostly around 5. I think they came from a large pond in the golf-course, which is behind our neighbors houses across the street. There is also a retention pond adjacent to our house which they sometimes hang out in. Last year we also had a koi pond put into our yard so that attracts them as well. We now have a kiddie pool for them behind the trampoline which is where they often hang out. They've just mated yesterday so i'm expecting some little ducklings nearby soon