Where are the cygnets

One of my friends at work and I came to this park a couple of weeks ago. There was a swan couple there, one nesting and the other hovering nearby. We thought we would go back today and see the cygnets, thinking  they would have hatched by now. When we got there we only found one swan. We walked around the park, but couldn’t find the other swan nor any cygnets, but we could here her. Unfortunately for us she was very well hidden apparently in the grasses growing at the edge of the water.