Foraging efficiency of two alpine bird species in central Japan

Abstract

ABSTRACT Capsule The foraging efficiency of Alpine Accentors Prunella collaris and Japanese Accentors P. rubida is highest on the snow surface in the alpine zone, where they forage for fallen arthropods. Aims To compare the foraging efficiency of two bird species across alpine habitats, including the snow surface, and discuss the impact of changes in snow cover on their foraging behaviour. Methods The foraging efficiency of two alpine bird species, recorded as the number of pecks per unit time, was compared in the alpine zone of Mount Norikura in central Japan, among four habitat types: snow surface, Japanese Stone Pine scrub, alpine tundra and scree. Results In total, respective 45 and 32 foraging sequences of Alpine Accentors and Japanese Accentors were recorded. For both species, foraging efficiency was markedly higher on the snow surface than in other habitats. Conclusion Alpine bird species exhibit high foraging efficiency on the snow surface in the alpine zone, assuming that prey sizes are similar across habitats. With the decreasing amount of remaining snowpack in the alpine zone, due to the general trend of climate change, bird species will likely have a shorter period to efficiently utilize these foraging habitats in the future.