You would think that stable yearly vole populations would be beneficial for owls, but this long-term study has shown that fluctuations in vole populations are much more advantageous for tawny owl populations.
Many other predators rely on small mammal populations such as foxes, weasels and stoats. Additionally, the article suggests that cycles of plant-eating insects may also be dampening, thus there may be a knock on effect on insectivores, such as hedgehogs and insectivorous birds.
The research showed that stable vole populations have more of an effect on owl breeding success than climatic conditions. However, the dampening of vole cycles may itself be affected by warmer wetter winters; a good example of changing climate having knock on effects further up the food chain.
Tawny owls are threatened with long-term decline because environmental change is dampening the population cycles of their favoured prey, a new study has shown. If the situation continues, the owls will slowly die out over the coming decades. Scientists analysed 27 years of data on owl populations and breeding patterns in Kielder Forest in Northumberland alongside the results of an earlier study. The latter showed field vole populations across Europe, which until recently fluctuated wildly from year to year, are becoming much more stable.