More Churchill polar bear captures due to increased vigilance not global warming

Polar bear specialists just don’t get it: virtually no one except the ever-gullible media believes their exaggerated stories of doom. Yet they keep trying and with every lie and misrepresentation of fact, they erode the confidence of the public. Unfortunately, it’s not just trust in polar bear specialists that’s being eaten away, it’s trust in science generally.

Churchill polar bear encounters up in 2015_CBC headline Feb 28 2016

This time, it’s a head-line grabbing piece about the number of problem polar bears in Churchill, Manitoba (written by Chinta Puxley) that made the usual media rounds yesterday (CBC News, CTV News, Global News, Huffington Post, Winnipeg Sun, The Globe and Mail). The main culprits are Daryll Hedman, regional wildlife manager for Manitoba Conservation, and polar bear biologist Andrew Derocher.

However, it’s hard not to see that the increased number of bears captured by Manitoba Conservation officers around Churchill can be best explained as a natural reaction by officials to a particularly frightening polar bear attack in 2013.

Here’s the offending quote:

Polar bear activity reports from the past three years show the number of documented cases in Churchill has jumped from 229 in 2013 to 351 last year.

The number of bears who were tranquilized and housed in the town’s holding facility, known as the polar bear jail, before being released into the wild almost doubled from 36 in 2013 to 65 last year.

Daryll Hedman, regional wildlife manager for Manitoba Conservation, said last year set a record for the number of polar bears caught within the populated “control zone” of Churchill.

“Three hundred and fifty-one — for occurrences, that’s a high number,” he said.

While Manitoba conservation officers have stepped up their patrols recently, Hedman and other experts say climate change is largely to blame. [my bold]

When I read that last statement, it seemed to me that “officers have stepped up their patrols recently” was almost certainly a huge understatement.

An almost-fatal attack occurred just after midnight on 31 October 2013. Polar bear patrols were more intense than usual because it was Halloween but several bears slipped through with devastating results. News of the attack grabbed international attention, with some blaming it on global warming.

A hyper-vigilant, zero-tolerance approach to bears near town in the years following that attack is an entirely expected reaction. In fact, many people might have called Manitoba Conservation negligent if they had not intensified their vigilance after that attack.

Independent Churchill polar bear guide Dennis Compayre, who left a comment at the Global News version of this story 28 February 2016, confirms that impression, although in his anger he’s confused the year of the attack (which was 2013, not last year):

“…there were more bears in jail last year in large part because of the aggressive style of the new “guns” in charge at Conservation Manitoba…the attack the year before [sic] put additional pressure on the cowboys to keep bears away…so the parameters widened and bears were being captured much further away from town.” [my bold]

The author consulted Andrew Derocher (University of Alberta) and by not checking her facts, repeated his lie about the size of the Western Hudson Bay population, which I discussed a few days ago:

“Andrew Derocher, one of the country’s leading polar bear experts based at the University of Alberta, said the population is in “grave condition.” The population has stabilized around 800 bears but few cubs are surviving past the first year, he said.” [my bold]

The official population size for WHB polar bears is 1030 – Derocher is deliberately misrepresenting the results of the last counts (Lunn et al. 2016; Stapleton et al. 2014) by quoting that number.See quotes from the Lunn et al. paper here.

The WHB polar bear population is currently stable, not declining – that’s not my opinion but the conclusion of the IUCN Polar Bear Specialist Group and Environment Canada (see map below). In addition, Lunn and colleagues found NO TREND in sea ice breakup or freeze-up dates since 2001.

EC_PolarBearStatusMapCanada_Oct 26 2014_direct

There is also no basis for Derocher’s claim that “few cubs are surviving past the first year.” No studies have been published on recent trends in cub survival – no matter how many time Derocher and his colleagues repeat this claim, they have no published data to back it up.

WHB Sea Ice and early breakup

Puxley constructed the story to support Hedman’s assertion that the increased number of incidents could be blamed on global warming:

“As the bears spend more time on land with less fat, they grow hungry and can venture into town in search of food. Where the first encounters with polar bears used to be late August, Hedman said polar bears are now coming into contact with people as early as July 1.

Breakup in WHB was a bit earlier than usual last year because of a highly unusual pattern of ice melt over Hudson Bay, a phenomenon not seen since 1990. Yet, as I pointed out in a previous post on breakup dates, in all of the papers that have been published that mention WHB polar bears and breakup dates, none of them mention 1990 as standing out for number of problem bears, starving bears, attacks, or anything else – 1990 was a non-issue.

See the Canadian Ice Service ice graph below for June 18 (1971-2015), noting that 30% ice coverage over the area of NW Hudson Bay is the threshold for bears leaving the ice. You’ll see how much 1990 stands out as an early breakup year, yet 2015 had about twice as much ice that week.

Hudson Bay NW same week 18 June 1971-2015

Sea ice in Hudson Bay usually melts from east to west (see NSIDC ice map below, for the June average, 2010):

June 2010 NSIDC

The pattern of ice melt seen in 1990 and 2015 (25 years apart, see maps below for June each year) were highly unusual and cannot obviously be blamed on “global warming.”

June 1990 NSIDC

June 2015 NSIDC

 

References
Lunn, N.J., Servanty, S., Regehr, E.V., Converse, S.J., Richardson, E. and Stirling, I. 2016. Demography of an apex predator at the edge of its range – impacts of changing sea ice on polar bears in Hudson Bay. Ecological Applications, in press. DOI: 10.1890/15-1256

Stapleton S., Atkinson, S., Hedman, D., and Garshelis, D. 2014. Revisiting Western Hudson Bay: using aerial surveys to update polar bear abundance in a sentinel population. Biological Conservation 170:38-47. http://www.sciencedirect.com/science/article/pii/S0006320713004618#

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