Make way for ducklings?

While I had the dogs out in the yard today--Lola on a leash, because I worry that she will run off--we witnessed something that first startled and then delighted me. The dogs were sniffing and exploring, as dogs will do, when Lola jumped back as something flew up out of the ground cover. Lucy never indicated that she even noticed, but I sure did--it was a female mallard duck! At first I was afraid she was hurt, because she only flew about 20 feet, landing on the driveway. The duck just stayed still. She didn't move for some time, long enough for me to find Tom and call him out to see. It was he that suggested the duck might be sitting on a clutch of eggs and that was why she didn't fly away. Is it a little late in the season for that? I don't know, but I prefer that scenario to an injured or sick bird. Anyway, I moved the dogs along, away from the area the bird flushed from, and when I looked again, the duck was gone from the driveway. I hope she went back to her nest--but I hate to frighten her by going out and looking more closely. How cool would it be to have a Mama Duck and ducklings in the yard?