Polar Bear Blog – Earth Day Update

Well, since its Earth Day (and also since I accidentally renewed by Internet Hosting Package for another 3 years…), its probably time for a Polar Bear Alley update.

Its been an eventful winter for Churchill’s polar bears.  First, they had a late start to the season; the bears didn’t leave Churchill until early December and the ice wasn’t really locked for some time after that…  Things got a bit ‘weird’ in that last week of waiting but the coast emptied out pretty quick once the ice did show up.

You could see open water from Churchill for another three weeks or so after freezeup, however, further down the Cape it seemed a bit more stable.  A slow freeze is also not necessarily bad for bears, it ‘may’ give them a bit more time for early season seal hunting before the ice gets too heavy.  Things actually get tougher for bears in January and February, the ice is just too thick to get at the seals effectively.

Of course, none of this compares with the seal bonanza that awaits in spring.  While bears hit their lowest weights in early March, for the next three months, they will fatten up, gaining about 80% of their annual caloric intake.  It is a critical time.

Unfortunately, things do not look great this year.  Two major storms hit the coast of Hudson Bay in March, with significant snowfall and 100km+ winds.  This was some tricky timing.  These storm events hit right when mothers with young cubs are first emerging from their dens.  These dens are built on the lee side of thermokarst lakes, a place designed to catch snow in the fall.

These snowfall events will have placed a major stressor on this year’s cub population.  These families must make a 10-12 day journey to the coast, a lot of fresh snow would increase the energetic demands of this journey.  Plus, it seems plausible that some dens may collapse under the added weight…?  Either way, March was not kind to Churchill’s bears.

The other challenge is that these storms likely added a layer of snow over the seal birthing lairs as well.  This could make it harder for polar bears to hunt this spring, making it more difficult to break into the den and also making it more difficult to smell the seals in the first place.  Weather continues to stay below normal along the coast.

Finally, reports from Arviat area are saying that there’s not a lot of seals around, both this year and last year.  This seems to gel with what researchers have been saying as well.  So, not to be gloomy, but an already low seal population combined with a heavy spring ice… tough times.

This pattern seems to be in keeping with the last El Nino/La Nina event in Churchill circa 1998 thru early 2000s.  A return of late freezeups, crash in seal population, heavy spring ice…  What we have yet to see is an extreme early spring breakup, hopefully that is not coming this year.

The frustrating part is that science and local observations have shown us how these bears fought to recover from the last El Nino; how they have adapted and how the population has started growing again, albeit a modest increase.  It is not a linear progression of declining ice, warming temperatures and bear populations but almost a series of steps, until we hit that final tipping point.

For whatever reason, strong El Nino/La Ninas have a real effect on Hudson Bay’s weather patterns.  Over the next couple years, we should really be watching spring breakup – if the ice holds until mid or late July, this population should continue to be stable but if it breaks up in June either this year or next, expect another 20%-30% population decline, maybe over just a season or two.

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