The size of the knob usually denotes if the swan is a male or a female. Now, having said this, we have seen females with larger knobs than the males. Again, usually, but not always, the larger the knob the better the chances are that the swan is a male. You cannot tell the age of a swan by looking at the bird.

You would have to be physically present when the swan is hatched and follow it yearly to know for sure. Size and lack of feather or bill coloration usually means that the sean is either a cygnet (baby) or juvenile. Once the bills turn reddish orange and the feathers are fully white, then it is surmised that the swan is an adult. The Regal Swan