Afew weeks ago I came downstairs and discovered I had left the freezer door open overnight: what a pain. We had to eat up the mushy produce as quickly as possible and some of it ended up going to waste. But my tribulations were nothing compared to the problems that Canada jays are having with their freezers right now.
As winter approaches Canada jays collect up all sorts of treats to see them through the winter – juicy beetles and centipedes, mushrooms, berries, little voles and mice. These tasty morsels are hidden throughout the forest and help to see them through the lean winter months. But new research, published this week in Royal Society Open Science, shows that Canada jays living at the southern edge of their range in Algonquin Provincial Park, Ontario, are struggling. The data shows that over the last 40 years the number of winter freeze-thaw events has increased. It appears that this frequent defrosting of the jays’ winter larders is leaving the birds hungry and unable to bring up large broods the following spring.
Many other species also rely on sub-zero winters to keep their food supplies fresh. For all of them climate change is reducing their range and forcing them to keep moving polewards.