I have a small pond in back of my house. We live in Massachusetts. A pair of swans have been nesting there for the past two months. They now have 8 babies. Before they were hatched ( about 2-3 weeks ago)the male swan left. I have seen him come back a few times but mostly the female is by herself. Why would he leave? At first I thought something happened to him. Will they all leave or will they stay for the summer?