Usually, the larger the knob, the more probable that the swan may be a male. However, this is not a guaranteed way of determining gender. We have seen female swans with males that have smaller or the same sized knob as the females. Additionally, a juvenile swan's knob may not be fully developed which would give the appearance of no or smaller knob.

You are correct in assessing the safety of the area from coyotes or other predators may be the reason she is staying in that particular area. Please let us know if she hatches any cygnets. The Regal Swan