The effect of recreational homes on willow ptarmigan (Lagopus lagopus) in a mountain area of Norway

The increasing development of recreational resorts and second homes in mountain regions worldwide require substantial infrastructure, and have large impact on habitats and ecosystems. We hypothesized that developed areas would attract predators and lead to higher predation on willow ptarmigan and lower their abundance. In a 500-km² study area in south-central Norway, we sampled the density of territorial cocks in spring and the breeding success of willow ptarmigan along a 3-km gradient extending out from clusters of cabins. We also sampled red fox scats and corvid birds and measured nest predation on artificial nests across this gradient. Densities of cocks in the spring and of adults and brood sizes in August did not vary along the gradient. However, the density of chicks in August was higher beyond 1.5 km from cabin areas, presumably because more hens lost their clutches in the vicinity of cabins. This was supported by the results from the artificial nest experiment where significantly more nests were depredated near cabin areas than further away. The number of scats of red fox along trails increased with distance from cabins, whereas more corvid birds were observed near cabins. We conclude that corvid birds were the main cause of higher loss of ptarmigan nests near cabin areas, which led to lower production of chicks. Breeding density, however, did not seem to vary along the gradient, presumably because of suitable habitat for breeding and little human activity in these areas during the period of pair formation and nesting.