Category Archives: Life History

Tracking polar bears in the Beaufort Sea – March 2015 map

Posted on April 7, 2015 | Comments Off

Here is the March 2015 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here). The USGS track map for March 2015 is copied below.

Three out of eight female bears tagged in the Southern Beaufort Sea were in the Chukchi Sea subpopulation region during March – not surprising, many bears cross this “boundary.”
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Posted in Life History, Sea ice habitat

Tagged Beaufort Sea, Chukchi Sea, polar bear habitat, polar bear movements, polar bears, satellite collars, sea ice, Southern Beaufort, spring, subpopulation boundaries, tracking polar bears, USGS

Superb sea ice conditions for polar bears worldwide during their critical feeding period

Posted on April 3, 2015 | Comments Off

Prognosis, excellent. The sea ice hunting platform that polar bears require is everywhere and Davis Strait ice extent is the fourth-highest it’s ever been at this time of year.

The spring feeding period is a messy, brutal business – many cute baby seals will die as polar bears consume 2/3rds of their yearly food supply over the next few months (April – June/early July), while sea ice is abundant.

That leaves the remaining 1/3 of their energetic needs to be met over the following 9 months (most of it in late fall (late November/December) and hardly any during the summer months, regardless of whether the bears are on land or out on the sea ice) or over the winter. Continue reading

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Posted in Life History, Sea ice habitat

Tagged breakup, Davis Strait, habitat, harp seals, Hudson Bay, hunting platform, polar bears, ringed seals, sea ice, sea ice extent, seals, spring ice maximum

Polar bear consumption of terrestrial foods – new paper misses the point

Posted on April 1, 2015 | Comments Off

A new paper by polar bear biologists (Rode et al. 2015) argues that terrestrial (land-based) foods are not important to polar bears now and will not be in the future – a conclusion I totally agree with – but they miss the point entirely regarding the importance of this issue.

Whatever food polar bears consume in the summer – whether they are on land or on the ice – doesn’t really matter. What matters is how many fat-rich seals they can consume between March and June each year. The fat put on in late winter/spring from gorging on baby seals carries polar bears over the summer, no matter where they spend it.

USGS polar bear biologist Karyn Rode and colleagues (press release here) have tried to frame this issue as one about future survival of polar bears in the face of declining sea ice. However, the fact that polar bears in the Chukchi Sea and Southern Davis Strait are thriving despite dramatic declines in summer sea ice (aka an extended open-water season), proves my point and disproves their premise. Bears in these regions are doing extremely well – contrary to all predictions – because they have had abundant baby seals to eat during the spring (see here and here).

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Posted in Advocacy, Conservation Status, Life History

Tagged Amstrup, Arctic, bird colonies, caribou, Chukchi Sea, climate change, Davis Strait, East Greenland, geese, global warming, goose eggs, habitat, InsideScience, polar bear, red herring, Rode, sea ice, sea ice loss, seabird eggs, Svalbard, terrestrial foods, us geological survey, USGS

Polar bear habitat update – even more ice this week in the Barents Sea

Posted on March 26, 2015 | Comments Off

Polar bear habitat is close to average for this date all over the Arctic this week. Barents Sea pack ice has increased substantially since last week and the ice in Eastern Canada is still well above average (and higher than 1979-early 1980s). Arctic ice has grown since a preemptive call for “the lowest maximum extent on record” was made by NSIDC last week — there is now at least as much ice for this date as there was in 2011 and almost as much as there was last year (2014).

Southern Davis Strait polar bears are out feeding on the glut of harp seals in the pack ice off Labrador and Newfoundland (discussed in detail here). One or more bears strayed a bit from the pack and ended up swimming around near the Hibernia oil platform (not far from the ice edge, although the CBC reports didn’t mention that “minor” fact), discussed in this recently updated post (with maps).

Harp seal female with nursing pup, DFO Canada.

Ice maps and graphs below: it’s worth a look.
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Posted in Life History, Sea ice habitat

Tagged Barents Sea, Canadian Ice Service, CBC, denning females, Derocher, harp seals, Hibernia, Hopen Island, Labrador, Newfoundland, Norwegian Ice Service, NSIDC, oil platform, polar bears, sea ice, sea ice maximum, Svalbard, swimming

Polar bear visiting Hibernia oil platform off Newfoundland was not far from sea ice

Posted on March 24, 2015 | Comments Off

Perhaps the folks on the platform couldn’t see it, but sea ice wasn’t far off on Monday when a polar bear came to visit the Hibernia oil platform southeast of St. John’s, Newfoundland. See the map below (composite from Heritage Newfoundland and Canadian Ice Service):

UPDATE 26 March 2015: Ian Stirling has added his expert comment on this incident, see below.

UPDATE 28 March 2015: Newfoundland’s Director of Wildlife has commented on this incident, see below.
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Comments Off on Polar bear visiting Hibernia oil platform off Newfoundland was not far from sea ice

Posted in Life History, Sea ice habitat

Tagged Davis Strait, Hibernia, Newfoundland, oil platform, Pagano, polar bear, sea ice, sea ice maximum, swimming

Polar bear habitat update – more spring sea ice around Svalbard than 2014 & 2012

Posted on March 20, 2015 | Comments Off

Polar bear habitat for the last week of March is well above average in eastern Canada for the second year in a row. The very low extent of ice in the Sea of Okhotsk – which has contributed strongly to the low maximum extent this year – is irrelevant to our discussion, since no polar bears live there.

There is a bit more concentrated ice around Svalbard than last year (or in 2012), although ice in the Barents Sea in general is still below average due to the state of the Atlantic Multidecadal Oscillation (AMO). The state of the AMO and its effects on Barents Sea polar bear sea ice habitat has nothing to do with global warming: it’s a cycle that has been documented for centuries (Miles et al. 2014).

Still, there is plenty enough sea ice for polar bear hunting: this is the beginning of the critical feeding time for all polar bears (see here and here), but especially for the survival of new cubs-of-the-year, so I have a few words about Western Hudson Bay cubs below.

Have a look for yourself.
Update: Added 20 March 2015, comparison maps from Cryosphere Today for 2006 vs. 2015.
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Comments Off on Polar bear habitat update – more spring sea ice around Svalbard than 2014 & 2012

Posted in Life History, Sea ice habitat

Tagged AMO, Barents Sea, Churchill, cubs of the year, Davis Strait, Norwegian Ice Service, polar bear, sea ice, spring ice conditions, spring ice maximum, Svalbard, western hudson bay

Tracking polar bears in the Beaufort Sea – February 2015 map

Posted on March 15, 2015 | Comments Off

Here is the February 2015 follow-up to my post on the July 2013 track map for female polar bears being followed by satellite in the Beaufort Sea by the US Geological Survey (USGS) – “Ten out of ten polar bears being tracked this summer in the Beaufort Sea are on the ice.”

See that post for methods and other background on this topic, and some track maps from 2012 (also available at the USGS website here). The USGS track map for February 2015 is copied below.

There were 7 bears in February, up from 6 in January, because one of the bears has re-entered the area from elsewhere. However, many bears from the original sample have either had their collars fail, moved out of the area and stayed out, or they have died. We can’t tell from which of those options, or combinations of them, explain the reduced number still being followed.
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Posted in Life History, Sea ice habitat

Tagged Beaufort Sea, Chukchi Sea, polar bear habitat, polar bear movements, polar bears, polar bears in winter, satellite collars, sea ice, Southern Beaufort, tracking polar bears, USGS

Polar bear biologists try – again – to blame S. Beaufort thick spring ice on global warming

Posted on February 13, 2015 | Comments Off

The trouble is, sea ice researchers and atmospheric scientists have not drawn that conclusion, despite what a new paper by Pilfold and colleagues imply. It shows just what lengths desperate IUCN Polar Bear Specialist Group (PBSG) biologists will go to in order to link the recent decline of Southern Beaufort bear numbers to global warming while ignoring similar past declines.

Comments Off on Polar bear biologists try – again – to blame S. Beaufort thick spring ice on global warming

Posted in Advocacy, Life History, Sea ice habitat

Tagged Beaufort Sea, climate change, Derocher, Eastern Beaufort, extinction, feeding, future, global warming, IUCN Polar Bear Specialist Group, models, Pilfold, polar bear, population, predation, predictions, Red list, ringed seals, Southern Beaufort, Stirling, thick spring ice, threatened

Polar bears out on the sea ice eat few seals in summer and early fall

Posted on February 9, 2015 | Comments Off

We hear endlessly about the polar bears ‘forced’ to go without food for months because of receding summer sea ice — what about all the bears that stay out on the ice over the summer? Presumably, those bears keep hunting for seals – but how many do they actually catch?

[Update 9 February 2015: Just to be clear, this post is based on the facts available in the peer reviewed literature — if you think I have missed something, let me know via the “Contact us” page above]
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Posted in Conservation Status, Life History, Sea ice habitat

Tagged Arctic, Beaufort, Central Canadian Arctic, declining sea ice, fall, feeding, feeding platform, gorging, hunting, hyperphagia, Pilfold, polar bear, seal kills, seal pups, seasons, spring, Stirling, summer, terrestrial foods, winter

East Greenland polar bears – said to be the most polluted but appear to be doing just fine

Posted on February 4, 2015 | Comments Off

I’ve not written much about this subpopulation before but with the flurry of interest over “weakened” penis bones and toxic chemicals, I thought it was time to remedy the situation.