Sample of photographs
We amassed 693 photographs of which nearly 80% were community-sourced and spanned years 1948 to 2018 from the entire distributional range of mountain goats (Figure 1) with the exception of Nevada and the Northwest Territories (NWT). Broken down by sources of data, professional photographers were our main source of photographs (N=203) followed by the CitSci platform (185), iNaturalist (126), researchers (Caw Ridge, Alberta, and Glacier National Park (GNP), Montana: 58), members of the public by e-mail to the lead author (15), members of professional societies including B.C. Mountain Goat Society, Wilderness Society, Summit Post (13), and other sources (4). Our 2018 southern Yukon sample included 58 photographs from YWP and 31 from the three wild sites. Mountain goats at GNP (where mountain goats are habituated in some locations) were most photographed by the public and by one professional photographer in particular (Sumio Harada), followed by Mt. Evans, Colorado (where mountain goats are introduced and also habituated to people) while Caw Ridge and Yukon were third and fourth with data provided by researchers (including the authors and inclusive of camera trap photos). Most but not all of these photographs (635 of the 693) were included in the analysis (see Statistical Analysis and Results). Finally, and even if photographs were submitted with elevation data, we used provided geo-referenced locations of all photographs to source elevation in meters for each photo from the Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010).