Results
The intensity of night light varied significantly between post-2009 records from each data source (ANOVA; F3, 1952 = 22.76, p < 0.001, figure 1a), as did GBIF-calculated habitat suitability (ANOVA; F3, 1947 = 73.14, p < 0.001, figure 1b). Broadly, occurrences obtained from GBIF and Flickr were found in areas of similar habitat suitability and urbanisation. At GBIF and Flickr occurrences, habitat suitability and urbanisation differed from those at Instagram and iNaturalist occurrences. Occurrences from Instagram were from areas with the highest measure of urbanisation (Table 2). When Italy was removed from the study area, occurrences from GBIF and Flickr were found in areas of significantly different measures of urbanisation but no other results were affected (Figure S4).