One thing the will not nor can not be reflected in winter mortality stats is fall combining. I think there has been a significant shift toward trying to have maximum spring numbers by outfits that intend to do pollination. 

A honey producer would logically only attempt to overwinter the best colonies, with the intention of making splits in the spring. A pollinator might try to winter marginal colonies on the odds that they might make it. 

With the shift over the decades from honey production as the primary source of income to pollination, this process could affect winter mortality where sub-par colonies would be kept as opposed to the smarter move of cutting losses in the fall. 

As we know, beekeepers in Canada reduced winter mortality to zero, by killing off the bees in fall. I think we all could similarly reduce winter losses by being far more strict about which hives to keep. 

I will try to find some numbers on this, but one must bear in mind that winter loss = loss of the number of hives one attempted to winter, not summer number maximum, which would be more telling. 

Pete

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