Intrapopulation variation in habitat use of an alpine ungulate: mountain goats in Kitasoo Xai'xais Territory

Intraspecific variation in space use among wildlife arises from different selective pressures facing individuals within populations. Such variation is important for wildlife management, especially when differences occur among reproductive individuals, juveniles, or other demographically significant groups. Age- and sex-specific segregation is common among ungulates, including mountain goats ( Oreamnos americanus (Blainville, 1816)). We hypothesized that mountain goats with and without kids would exhibit different space use in a peripheral population inhabiting Kitasoo Xai'xais First Nation Territory on the coast of British Columbia, Canada. Using aerial survey data from August 2019 and 2020, we fit multi-state occupancy models to estimate mountain goat habitat use in relation to landscape features. We predicted that groups with kids would preferentially use more rugged areas with ample escape terrain, while groups without kids (including solitary males and non-reproductive individuals) would use areas with greater forage availability. We found that the probability of mountain goat occurrence increased with elevation ( p < 0.001), while the probability of detecting kids, conditional on presence, increased with terrain ruggedness ( p < 0.001). These results suggest that pooling observations across group types may obscure important habitat use patterns and caution is warranted when delineating habitat or managing activities such as hunting or aerial tourism.