If the rain was heavy and enough oxygen was displaced from the lake to produce an anaerated environment, deadly bacteria and their toxins could still be responsible. It is extremely difficult to diagnose without a necropsy.

It is not likely that a goose killed her, but if she was attacked in the wrong spot (an area of the spinal cord or neck with no visible external injuries) then, she could have died from internal injuries. In most instances, swans are more aggressive to geese and the gesse are afraid of the swans, but I have seen male trumpeters extremely frightened by geese. So, this could be the answer.

Now, some swans do tolerate another mate and others will go through life without a mate. We would suggest that you give it a couple of weeks to insure that whatever killed the first swan does not come back to finish the second one. If you get another swan and the second one dies for whatever reason, then you are only continuing the process of getting a swan to replace one. You will need to keep the new swan in a pen to ensure that there is no aggressiveness for a couple of weeks for introduction to Lily.

Finally, are you sure that you cannot get a male swan? The Trumpeter swans are indigneous (native) to North America (as well as the mute swans but most researchers/biologists fail to recognize this fact). If the swan is pinioned (cannot fly) and you pinion the cygnets at an early age (1-3 weeks of age) you may be able to procure a male. However, if you do not wish to have cygnets and there is indeed a state law, then a female swan may be the answer.

We would suggest that you speak with Bob from Knox Swans. He may be able to sell you another swan as a mate or take Lily and place her with a male on another pond and provide you with a new pair. Good luck. Please let us know how this situation turns out. The Regal Swan