Climate change affects temperature and landscapes, especially in northern latitudes where heavy winters are becoming less common. Changes in the environment can strongly affect animals locally adapted to their habitat. Camouflage and insulation play a key role in the survival of many animals. For predators, changes in camouflage abilities due to environmental changes can affect the probability of being detected by prey species, thereby affecting hunting success and predator-prey interactions. The tawny owl, Strix aluco, displays two genetically determined colour morphs, the grey and the brown morph, with some variation in the degree of pigmentation of pheomelanin in their plumage. Grey morphs have higher survival rates than brown morphs in snowy winters and are known to be more cryptic in snowy landscapes. In this thesis, I used experimental approaches to study camouflage effects on the behaviour of predators and prey. I investigated local adaptation by comparing phenotypic traits with genetic data. I first studied tawny owls' camouflage behaviour and space use in a novel environment. Neither morph showed evidence of background matching when using behavioural tests in controlled conditions. However, brown, tawny owls often perched in the exposed area, indicating boldness. Then, I assessed the significance of camouflage under variable environmental conditions by quantifying passerines’ mobbing behaviour against stuffed owls during four different environmental conditions. The detection probability by potential prey never differs between the two morphs. However, the grey morph had a higher probability of being mobbed in the absence of snow cover than the brown morph and the mobbing probability was reversed in the presence of snow cover. Finally, I measured feather insulation capacities in nine different tawny owls’ populations in Europe. The results showed only population differences in insulation capacities but no morph differences. Therefore, The two colour morphs experience differential benefits across snow conditions, which may help maintain colour morphs in the population, although further warming of winter climate is expected to shift tawny owls’ population dynamics in northern latitudes.