The lake in the gardens behind Sizergh Castle is home to a pair of mute swans. They have built a nest on the island in the lake and one of the pair was on the nest, though I couldn't see if there were eggs laid. The other (I presume the male) was gliding around, feeding. Swans usually mate for life and use the same nest year after year, rebuilding it as necessary. Both take turns to guard the nest.
I was on a raised terrace so perhaps the swan didn't spot me. At any rate, for once, I got decent photos. Swans usually turn their backs and hide their heads as soon as they see me! What was captivating was how clear the water was, so that I could see the bird's head under water and watch how it was feeding. Fascinating.