I seem to have some nesting doves in my back yard.  The nest is very low (about 8 feet above ground) and located in one of my trees.  When I go into my back yard, the sitting dove (he/she?) is very still and I do not want to engage in any activity causing the nest to be abandoned.  Problem is, I need to do some work, i.e., cut grass, trim bushes, etc.  I use an electric lawnmower but it is still loud and may frighten the dove away from the nest.  What to do?  Suggestions appreciated.