Interspecific competition limits larders of pygmy owls Glaucidium passerinum

摘要

To test whether competitive and predatory interactions limit larder size we erected pygmy owl Glaucidiumpasserinum nest-boxes for hoarding with 45 mm entrance diameter near and far (> 2 km) from Tengmalm's owlAegolius funereus nest-boxes with >80 mm entrance diameter during early autumn. We found larders of pygmyowls in similar frequency in both near and far plots (41 vs. 42% of plots), but in near plots the number andbiomass of cached prey by pygmy owls were lower. These results suggest that there is competition for foodbetween these two owl species and/or that food caching behaviour of pygmy owls is disturbed by largerTengmalm's owls.