On the prairies we experience generally cold conditions for about five months. The relative humidity is moderately high, since air at low temperatures cannot hold much moisture. Most of the water in the hives in winter comes from the bees themselves. My wintering technique seems to deal with these conditions fairly well, but may involve more time than a serious commercial beekeeper could afford. First, I use a year-round insulated inner cover. The cover consists of a plywood box 16.25" wide, 20" long and 1" deep. A piece of styrofoam is cut to fit snugly inside. The box is covered top and bottom with .25" plywood. A rim .25" thick and .75" wide is applied both top and bottom and a section of the rim about 2" long is cut out for an upper entrance. The styrofoam acts as its own vapour barrier. In the winter I use the cover with the upper entrance and in the summer I turn it over so that the bees must use the lower entrance. Second, I arrange my hives in groups of 5 in a row on two rails made of 2x8 lumber 10' long. In summer the hives are slid apart and in winter they are slid back together. I place a 1" piece of styrofoam at each end and hold the whole thing together with two 8' pieces of redi-rod through plywood pressure plates at each end. Third, I place a 24" wide by 83" piece of styrofoam at the back of the hive and hold it there with 6 large wedges between it and the redi-rod. Another piece of styrofoam 19" wide by 83" long goes on the front and is held on with wedges as well. Fourth, I cover the whole thing with a piece of plywood which has a 1X6 nailed on the back to prevent wind blowing through. I hold the lid on with some rocks; the 1X6 keeps it from sliding forward. Naturally the entrances are to the south, and fortunately the winds here are from the north. Finally, the lower entrances are shut almost completely. I leave a .25" by .75" opening to let water drain out. The rails are arranged to tilt the hives slightly forward. Closing the bottoms serves also to keep mice out. I have had quite good success with these wintering methods over a 15 year period. Thicker styrofoam does not improve things much. Each yard, of course, has 1,2,3 or 4 orphans in the fall. I have been leaving these to their own devices and find that in good winters the uninsulated ( except for the inner covers ) hives survive fairly well. Last year we had a particularly savage winter and the uninsulated ones all died. Henceforth I will make an effort to collect these odd ones and insulate them. Donald Aitken 11710-129 Street Edmonton Alberta Canada T5M 0Y7