Roe deer and mountain hares are known to select same food sources and engage in indirect exploitative competition. Here we report on a case of direct interaction between a roe deer doe and a mountain hare recorded by a camera trap in Tydal Municipality, Norway, suggestive of direct interference competition. The roe deer doe is as a minimum following and displacing the mountain hare for 2 minutes and 29 seconds, including a 19 second active chase phase. Although this could be just a case of curiosity, we suggest this is a case of interference encounter competition between these two herbivore species, previously not documented. Our traditional textbook understanding of ecology is based on the common and the easily observable, not the rare and difficult to observe. This observation paints a different picture of our understanding of the interactions between roe deer and hares, as roe deer may compete directly with mountain hares over food resources.

Local adaptation to annually changing environments has evolved in numerous species. Seasonal coat colour change is an adaptation that has evolved in multiple mammal and bird species occupying areas that experience seasonal snow cover. It has a critical impact on fitness as predation risk may increase when an individual is mismatched against its habitat’s background colour. In this paper we investigate the impact of landscape covariates on moult timing in a native winter-adapted herbivore, the mountain hare (Lepus timidus), throughout Norway. Data was collected between 2011 and 2019 at 678 camera trap locations deployed across an environmental gradient. Based on this data, we created a Bayesian multinomial logistic regression model that quantified the correlations between landscape covariates and coat colour phenology and analysed among season and year moult timing variation. Our results demonstrate that mountain hare moult timing is strongly correlated with altitude and latitude with hares that live at higher latitudes and altitudes keeping their winter white coats for longer than their conspecifics that inhabit lower latitudes and altitudes. Moult timing was also weakly correlated with climate zone with hares that live in coastal climates keeping their winter white coats for longer than hares that live in continental climates. We found evidence of some among year moult timing variation in spring, but not in autumn. We conclude that mountain hare moult timing has adapted to local environmental conditions throughout Norway.