Climate Change May Melt the “Freezers” of Pygmy Owls and Reduce Their Overwinter Survival

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Ecologists at the University of Turku, Finland, have discovered that the food hoards pygmy owls collect in nest-boxes ("freezers") for winter rot due to high precipitation caused by heavy autumn rains and if the hoarding has been initiated early in the autumn.

Ecologists at the University of Turku, Finland, have discovered that the food hoards pygmy owls collect in nest-boxes ("freezers") for winter rot due to high precipitation caused by heavy autumn rains and if the hoarding has been initiated early in the autumn. The results of the study show that climate change may impair predators’ foraging and thus decrease local overwinter survival . The study has been published in the internationally esteemed Global Change Biology journal.

Doctoral Candidate Giulia Masoero together with co-authors from the Department of Biology at the University of Turku analysed the unique long-term data set collected by Professor Erkki Korpimäki and his research group in 2003–2018. The aim was to study how the changing weather conditions in late autumn and winter affect the initiation of pygmy owls’ food hoarding as well as the accumulation, use and preservability of the hoarded food. The data set was collected from the Kauhava region in South Bothnia with over 500 food hoards and a research area covering 1,000 square kilometres.

Pygmy owls are small predators that feed on small mammals, especially voles which are their main prey, and birds. Pygmy owls start hoarding for winter usually in late October when the temperature drops below 0° C. They hoard a large amount of prey in tree cavities or nest boxes.
The food stores may be located in multiple nest boxes some   kilometres apart. Female owls that are larger than males as well as young owls accumulate larger food stores than males and adult owls.

Read more at University Of Turku

Image: Pygmy owls.  CREDIT: University Of Turku