The main part of the collection is the exquisite bird collection, in which a large number of the region’s native breeding birds are represented. The focus is on bearded vultures and golden eagles, for whose protection Carl Stemmler strongly advocated. To prove that the legend of the child-eating golden eagles is false, he collected material from numerous nests and preserved and documented their contents.

Carl Stemmler was a furrier by profession. Thanks to this activity and his impressive network, the collection also includes numerous specimens of native mammals and furs from all over the world. As a template for preparations, he drew detailed views of the animal bodies. He also photographed numerous bird species. These artistic creations are also part of Stemmler’s unique collection.