During the last 30 years, we could observe several thermophile butterfly species drastically expanding their distribution range across Switzerland. Many factors are considered as possible reasons, like climate change or phenological mismatches. As part of my master's thesis, I will try to disentangle this case with a species distribution modelling approach. My MSc project is a joint collaboration between the Nature History Museum Bern and the Terrestrial Ecology Group of the University of Bern.