We're not sure that the swans are afraid of lightning and thunder as they are on ponds and lakes throughout their lives in fair as well as inclement weather. This fact would seem to support that they eventually get used to inclement weather. However, if the lightning and thunder is severe, they may be startled and look for some shelter from the noise and light.

As for the algae, it depends on the type of algae. If it is cyanobacterial, there could be a toxicity which could possibly be detrimental to the swan. If it is another type of algae or bacteria, then there is a possibility that the bacterial count could increase the propensity for botulinum toxin in the water. Again, unless the water and the algae are tested and identified, it is difficult to surmise the species and the possible consequences. The Regal Swan