Simplify the following text for a Grade 7 native English-speaking person.
Original: Swans , genus Cygnus , are birds of the family Anatidae , which also includes geese and ducks . Swans are grouped with the closely related geese in the subfamily Anserinae where they form the tribe Cygnini .
Simplified: They are in the subfamily Anserinae , in the family Anatidae , which also includes geese and ducks .