The most obvious interaction between Gavia immer and another organism is between the loon and its prey. As mentioned on the Nutrition page of this site loons enjoy a variety of different fish and other aquatic prey. This is a predatory relationship and serves as a nutritional benefit to the loon.

     Another, not so beneficial, interaction occurs between Gavia immer and the parasite, Clostridium botulinum. This parasitic bacteria affects many species of birds that is caused by the consumption of contaminated food. Type E botulism is the strain that most often affects loons and require it as the final host in its life-cycle. Because loons eat live prey only and fish infected with botulism are usually not living, it is interesting how they acquire this nasty parasite.  Gavia immer sometimes eat baitfish that have a trace of botulism. The bacteria is not enough to kill the fish, but it is enough to infect the loon! According to Loon Magic, an outbreak on Lake Michigan in 1963 killed about 6,780 loons. Lakes where loons choose to reside usually do not have a problem with botulism. Because of this loons have a very low immunity to the bacteria. Other birds like pigeons also exhibit this low immunity, where as turkeys show a higher tolerance.