You might also want to consider cold winter flight as being instinctual 
behaviour.

What I mean is bees tend to prefer to die away from the bee nest during 
times of good flight weather.  They get old, they fly off to die.  I 
figure they do also during winter as they get a chance to break cluster.

I often find bees several hundred meters away from the bee yard laying 
dead ontop of snow banks mid winter.  I really doubt they are flying that 
far to releave themselves.  It has to be releated to something more 
instinctual.

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