We need additional information about your swan. Is the behavior seasonal? If it is, this is normal as the hormone levels for mating will increase territorialism.

When did the behavior first appear? Was there some trigger point, i.e., fear of a human or animal (dog, cat, wildlife) so that the swan felt threatened? If so, this is going to be hard issue to overcome as the bird may feel threatened by all humans or animals. The behavior may not be aggressive, but rather defensive in nature. This is not a bad thing because if you try to curb the swan's defensive behavior to all humans and animals, it will not be able to protect itself when a true threat exists.

Is the swan more friendly towards you rather than your husband or other male? If so, this is classical imprinting and it thinks that you are his mate and it is his duty to protect you.

If the behavior is defensive and there are no true threats to the swan in your immediate area, there are several things that can be done. First, restrict his range. Allow him only to inhabit the area immediately on your property and even restrict him on the lake if this is possible. If this is not possible, then you have another option.

Any time his behavior becomes aggressive, capture the swan. Place him in a small safe area such as garage (no chemicals or fumes and safe from predators) or temporary pen (enclosed top to bottom to prevent any predators from accessing him- meaning you will need to prevent digging under the pen or climbing over and into the pen). A feeder should be placed in the pen. The garage, pen or other structure will be his time out room. Once he makes a run at you, capture him, say a loud no and place him in time out. Leave him in time out for an hour, but make sure he has access to shade, water and food. This process must be repeated each time he makes a run at you or another person. Sporadic time outs will not properly reinforce the new behavior.

It will only take a couple of times for this time out process to occur for him to understand that chasing or engaging humans is not a pleasant nor profitable venture as it restricts him from his pond and territory.

Finally, DO not get him another male as either of the swans could be serioiusly injured or killed due to the ensuring fights. If he is this territorial, he may try to kill any new swan, even a female. So, this is not a good idea at this time.

Should you try to introduce another swan, it would need to be a female and you will need to keep her in a safe pen (1/2 in water, 1/2 on land with feeder) for a couple of weeks to intoduce the swans to each other and to the new habitat. Should there be any signs of aggression, you will need to remove the new bird from the habitat. A female swan may calm him, but it could make him even more protective of the area and you will then have another issue of what to do with the cygnets once they are mature enough to leave the habitat. So, our best suggestion at this time would be to see if the swan can be conditioned through time outs to learn how to cohabit the area with other people and not provide him with a mate. Most male swans, especially those who have never had a mate or lose a mate, will live their lives comfortably without a mate. The Regal Swan