<em><u>Topiary is the horticultural practice of training perennial plants by clipping the foliage and twigs of trees, shrubs and subshrubs to develop and maintain clearly defined shapes, whether geometric or fanciful. The term also refers to plants which have been shaped in this way.</u></em>
Birds and butterflies don't have a common ancestor because one is a member of a insect and the other is well a bird. They both have different body structure. One has bones and the other has an exoskeleton. hope this helps