Social media data are becoming potential sources of passive VGI (Volunteered Geographic Information) and citizen science, in particular with regard to location-based environmental monitoring. Flickr, as one of the largest photo-sharing platforms, has been used in various environmental analyses from natural disaster prediction to wildlife monitoring. In this article, we have used bird photos from Flickr to illustrate the spatial distribution of bird species in Switzerland, and most importantly to see the correlation between the location of bird species and land cover types. A chi-square test of independence has been applied to illustrate the association between bird species and land cover classes and results illustrated a statistically significant association between the two variables. Furthermore, species distributions in Flickr were compared to eBird data, and the results demonstrated that Flickr can be a possible complementary source to citizen science data.