>But it is reasonable to say that if one combines and culls, one will lower
the winter loss rate by some fraction, no matter how mild the winter.

Not sure that it true - and I am not really clear whether culling means
uniting or just killing them off.

Let's start with 10 colonies.

Combine 2 with 2 others.  Now I have 8.  If the combined colonies die,
perhaps because of disease or queen failure, then I have 6 - a winter loss
of 25%.  If I had left them all, then perhaps just the 2 would have died,
giving a winter loss of 20%.

If I cull 2 before the winter then the starting number is 8.  Perhaps I lose
2 because they were weaker, perhaps I lose none!

Too many 'ifs'!

Best wishes

Peter 
52°14'44.44"N, 1°50'35"W

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html