Photo: 2 black swans with 5 cygnets in Centennial Park today

(download)

 

Wikipedia says a brood may have 4-8 eggs, so 5 chicks is average - not all will survive. The couples mate for life with a only a 6% divorce rate! see http://en.wikipedia.org/wiki/Black_swan

Update: 6 March - now only 2 cygnets surviving...