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Selecting a suitable calving site is important for ungulates, especially when predators are present. Brown bears (Ursus arctos) predate on moose calves (Alces alces) and therefore influence the reproductive success of the moose. Female moose learn to reduce the chances of predation on their calves, but it remains unclear which strategies female moose apply. Therefore, the aim was to study the effect of bear predation on the choice of calving site features and site fidelity of female moose. To study the effect of bear density on calving site choice, I compared calving site features (e.g. habitat structure like distance to the nearest road, vegetation cover and terrain ruggedness) with characteristics of random sites within seven areas with different bear densities in Sweden. To study the effect of bear density on site fidelity, I compared distances between successive calving sites between areas with varying bear densities and between females that lost their calves in the previous year compared to females with surviving calves. The effects were studied using movement data of female moose, survival data of their calves and maps of the site characteristics. Female moose in areas with bears selected for higher shrub cover, higher tree cover and slightly lower distance to the nearest road compared to females in the predator-free area. Shrub cover and tree cover both increase the chance of hiding the calf from predators. The selection for higher distance to roads was strongest in the predator-free area, which indicates that the presence of bears resulted in a selection closer to roads. The distance between calving sites during subsequent years was greater in areas with higher bear density compared to the area without bears, regardless of whether the female has experienced a calf loss or not in the previous year. There was no evidence that female experience with calf predation in the previous year had an influence on the selection in most weeks or on the distance between su

Climate warming in the Arctic has led to warmer and earlier springs, and as a result, many food resources for migratory animals become available earlier in the season, as well as become distributed further northwards. To optimally profit from these resources, migratory animals are expected to arrive earlier in the Arctic, as well as shift their own spatial distributions northwards. Here, we review literature to assess whether Arctic migratory birds and mammals already show shifts in migration timing or distribution in response to the warming climate. Distribution shifts were most prominent in marine mammals, as expected from observed northward shifts of their resources. At least for many bird species, the ability to shift distributions is likely constrained by available habitat further north. Shifts in timing have been shown in many species of terrestrial birds and ungulates, as well as for polar bears. Within species, we found strong variation in shifts in timing and distributions between populations. Our review thus shows that many migratory animals display shifts in migration timing and spatial distribution in reaction to a warming Arctic. Importantly, we identify large knowledge gaps especially concerning distribution shifts and timing of autumn migration, especially for marine mammals. Our understanding of how migratory animals respond to climate change appears to be mostly limited by the lack of long-term monitoring studies.

Climate warming in the Arctic has led to warmer and earlier springs, and as a result, many food resources for migratory animals become available earlier in the season, as well as become distributed further northwards. To optimally profit from these resources, migratory animals are expected to arrive earlier in the Arctic, as well as shift their own spatial distributions northwards. Here, we review literature to assess whether Arctic migratory birds and mammals already show shifts in migration timing or distribution in response to the warming climate. Distribution shifts were most prominent in marine mammals, as expected from observed northward shifts of their resources. At least for many bird species, the ability to shift distributions is likely constrained by available habitat further north. Shifts in timing have been shown in many species of terrestrial birds and ungulates, as well as for polar bears. Within species, we found strong variation in shifts in timing and distributions between populations. Ou r review thus shows that many migratory animals display shifts in migration timing and spatial distribution in reaction to a warming Arctic. Importantly, we identify large knowledge gaps especially concerning distribution shifts and timing of autumn migration, especially for marine mammals. Our understanding of how migratory animals respond to climate change appears to be mostly limited by the lack of long-term monitoring studies.