My Buddy knows that Daddy is the one who does the lawnmowing around the house. As we have an acre & a quarter or so, we have a riding mower. Buddy stays in the house while Daddy is mowing, but he'll watch him from the window, and wave when Daddy goes by.
When he hears the mower coming, he'll run to the window, to see Daddy and wave (Daddy is usally concentrating on the lawn, and does not necessarily wave back though).
Our neighbours all have similar or larger parcels, so they also have riding mowers. Bud figures that any man riding on a mower is Daddy.
Have you ever tried to take your Baby for a walk down the street, and have him point at the neighbour on the mower and yell "Da! DA! DADADADA."