Cowbird:

 Cowbirds are unique in that they don't hatch their own eggs or raise their offspring.  They watch other species and when they aren't paying attention they will lay an egg or two in the other species nest. The other species hatches the cowbirds egg/s along with its own and raise the young cowbird/s. It is the height of laziness. 

It reminds me of a story of two old country boys sitting on the porch. The topic of having a family came up and the one said he would like a family,  He asked his buddy if he knew where he could find a pregnant woman. Like the cowbird that is the height of laziness.