Parasites

Society has too many members who are willing to live on the labor of others, like the shoveler duck described in this extract:

       One of the ducks has learned a convenient trick for getting his dinner. Some of the diving brotherhood who feed under water stir up a great deal that floats, and the shoveler, preferring to take his provision from
the surface, follows his diving neighbor to the feeding-place, and while the feeders below stir up the inhabitants, he swims around on the surface and catches whatever floats. Olive Thorne Miller, 'The Bird Our Brother."