As discussed here, a family tree on Geni, Ancestry, MyHeritage, Family Search, or any other user-generated tree (like WikiTree itself) is not a reliable source for a pre-1700 profile. If the Ancestry family tree you are using itself cites actual primary or reliable secondary sources, then cite and use those sources - but we cannot rely just on the Ancestry family tree itself.
Moreover, regarding the specific addition you are proposing, note that the profile for Robert Day right now, under "Disputed Origins", has the following:
Richard Day and Anna Kirby. Richard Day had a son Robert baptized 09 Jun 1604 at St. Mary, Kilburn, Yorkshire, England. One baptism does not a connection make. There are a half dozen other Robert Days baptized, recorded in currently indexed (at Family Search) in England between 1603 and 1606. We don't known which one is the father of the immigrant."