Good question! Swans are Sentinel birds, especially Mute Swans, which alert scientists to problems in the environment. THEY ARE NOT an invasive species as has been wrongfully reported for many years. A Sentinel or Indicator species is an animal, bird, plant or organism that signifies the health of the surrounding habitat. For instance, Mute Swans alert scientists to the presence of harmful microorganisms and the presence of heavy metals such as copper and lead. Because the swans are larger than most waterfowl, instead of dying from harmful bacteria or toxins, they may appear sick which can allow the testing of the birds while they are alive instead of dead. Smaller species may die from any interaction of bacteria or toxins and may not readily be seen once they become sick. An ill large bird like a swan in an area with people usually are noticed and reported.

If we allow the swans to die or kill them, then we are losing an early warning system to problems in the environment. Once this alarm is gone, then early intervention is also lost and the resulting problem can be catastrophic for the habitat and other species including humans. The Regal Swan