Churchill

Late this past fall I spent a week in Churchill, Manitoba to observe the Western Hudson Bay population of polar bears who were beginning to gather along the shore of the Bay as they waited for it to freeze over.  During the winter Hudson Bay freezes over and provides a critically important platform for the bears, who hunt and eat the ringed, harbour and bearded seals that live within the Bay.  Each year in early summer, though, the ice melts, forcing the bears onto land for the summer and early fall months, during which they largely fast, though some scavenge at the local town dump and some may successfully hunt an occasional caribou.

Churchill is unique, relative to the rest of Hudson Bay, in that it is located where the land juts out into the Bay, creating an obstruction that captures the gathering ice as it is pushed in a counterclockwise direction by the Bay’s currents and prevailing wind patterns.  This means that Churchill is where the ice typically first forms, providing the earliest opportunity for the bears to resume their hunting.

Historically, the ice-free period used to last an average of 120 days, a time of fasting that the bear population had adapted to over thousands of years.  Once the Bay froze over again each fall, the bears would head back out onto the ice to hunt seals, allowing them sufficient time to pack on the required store of calories that would help them to successfully survive the following year’s fasting period.  For pregnant females, having sufficient time out on the ice is even more critical since they need to accumulate sufficient fat stores to allow them to conceive successfully.  Bears mate in the spring but the females’ reproductive system do not allow fertilization of the eggs until the fall, so that the timing of the births of new cubs coincides with early spring.

But the impact of global warming, which is especially acute in the polar regions, is having a significant effect on the freeze-thaw cycle in Hudson Bay, with the thawing of the ice each summer occurring earlier and earlier, and the freezing again in the late fall occurring later and later.  This means that the number of days available to the population to hunt seals on the ice is becoming shorter and shorter.

Simply put, there are fewer and fewer ice days during which the bears can hunt on the ice, and an increasing likelihood that at a certain point, they will not be able to build up enough fat stores to enable them to survive through their enforced fasting.  This dynamic will likely first become manifest in the failure of females to conceive, due to a lack of sufficient energy reserves. Scientists are predicting that the last Western Hudson Bay cub may be born in as little as five years from now, signaling the reproductive end of the population and its eventual extirpation.  It is possible, though perhaps it is a remote possibility, that the population may somehow adapt, by moving to other areas in the Arctic, but most of the surrounding populations, such as the Southern Hudson Bay and Foxe Basin populations are suffering from the same dynamic.

If you are accustomed to images of big powerful polar bears, far out in the Arctic pack ice, hunting seals, Churchill is not that.  By the time they begin to gather along the shore in November, the bears are very hungry and playing a waiting game.  The sense of boredom and listlessness is almost palpable.  I found myself staring out at the Bay, silently wishing it would somehow freeze faster, so the bears could be released from the torture of having to wait. 

I left Churchill on Sunday November 3rd.  It was another full month until the Bay froze over in the Churchill area and the bears could finally head out onto the ice.  Relatively speaking, it was a good year for the bears, only having to spend about 141 days fasting.  But in the Southern Hudson Bay area, it was not a good year at all, with the bears in that population setting a record of 198 days fasting.