Each colony should have enough honey and pollen to last until spring. This means 40 to 60 pounds of honey and as many combs with areas of stored pollen as possible. In areas with long, cold winters, bees may need as much as 90 pounds of honey. A well-filled deep hive body with some empty space in the center combs provides enough stores for a strong colony wintered in two hive bodies. It is more difficult to rate the pollen supply, but colonies with a shortage can be given combs from other colonies or given stored combs that contain pollen. Combs can be filled with trapped pollen as explained on page 106. Colonies without sufficient honey should be given full combs saved for the purpose, or fed enough sugar syrup or diluted honey to make at least 40 pounds of stored food.
Bees winter best on combs that have been used for brood rearing. If possible, do not winter bees on all new honey combs, and be sure that any frames of foundation are replaced with drawn comb. Remove the excluder and all empty, supers. If you have no other place to store empty combs, you can leave them on the hive above an inner cover with the center hole open. However, it is better to store combs where they cannot be damaged or blown over by the wind. See page 108 for information on protecting stored combs.
Weak or queenless colonies should be united with stronger colonies that have queens. See page 131 for details on how to unite colonies. Colonies in a single brood chamber do not winter well in the Midwest. If you want to keep the individual small colonies rather than unite them, consider putting the small colony above a double division screen on a large colony. A double screen is a wooden frame holding two layers of wire screen, usually 8-mesh. The screens are sufficiently far apart that bees on either side cannot touch. A rim with an entrance cut in one end lets the division screen serve as a bottom for the top colony while the heat from the colony below helps to keep the smaller colony warm. To use the screen, remove the cover and inner cover of the large, colony and put the division screen in place with the entrance toward the back of the hive ( Fig. 47). Put the small colony above the screen after making certain it has a good supply of stored honey of at least five or six full frames.
Good management includes a careful inspection for disease in the fall. If you follow a program of disease prevention with drugs and antibiotics , each colony should be treated after the honey crop has been removed and while the bees are still active. See pages 136 to 137.
As the weather becomes cooler at the end of summer, field mice look for warm places to spend the winter. A nest in the lower corner of a bee hive is just such a place. For this reason it is necessary either to use the 3/8-inch entrance or to restrict any deeper entrance used during the summer. An entrance block, a piece of lath with an entrance slot, or a metal entrance reducer can be used. Do not make the entrance less than 4 inches wide or cover it with hardware cloth because the bees that die during the winter may block the entrance.
The colder the winters, the more the bees benefit from a top entrance to the hive. This entrance permits the escape of some of the moisture produced by the bees. The top entrance also lets the bees get out of the hive more readily during brief spells of sunny and warmer weather during the winter and spring when it is still too cool to allow the bees to move down to the main entrance of the hive.
A double division screen in place on top of a hive. The small entrance is suitable for winter but should be enlarged for use at other times of the year. (Fig. 47)
You can make a top entrance by boring a 3/4-inch hole in the top hive body near the front hand hold. Otherwise, you may cut a 3-inch by 3/8-inch slot in the front lower rim of the inner cover. Push the telescoping cover forward to provide access to the opening. Similar entrances can be made in one-piece covers by cutting a slot with a dado blade on a 'saw. Bees in central Illinois and the lower Midwest can winter well without upper entrances, and you need not worry about their survival if the lower entrance is covered by ice or snow -the bees will not suffocate.
Cellar wintering of bees and wrapping or packing of bees left out of doors were once common in the Midwest and elsewhere. These practices became less common as beekeepers tried to reduce the labor and expense of operating more colonies. They also believed the advice of beekeeping experts who said that strong colonies of bees did not need special protection but only plenty of stored honey and shelter from the wind. In part because the beekeepers took the experts' advice, half or more of the honey bee colonies in many areas of the Midwest died during recent severe winters. At the same time, beekeepers in northern Saskatchewan who had protected their bees with fiberglass insulation and roofing paper suffered only normal losses of 5 to 10 percent.
Colonies protected by wrapping or insulation eat less food during the winter and are better able to move their clusters to new areas of honey within the hive. With the heavy insulation used in northern Canada, the bees cluster loosely or not at all and do not fall victim to "cold starvation" when they lack food because move to reach it.
An apiary in winter. The snow fence provides wind protection until the evergreens grow taller. The hives face south and the slight slope allows air drainage. (Fig. 48)
Beekeepers in areas with cold winters should give their colonies some help in surviving the winter. Depending upon the local conditions, such help can vary from wrapping individual hives or groups of four hives with roofing paper to providing insulation or other packing. Wrapped colonies should have an upper entrance and a greatly reduced, or closed, lower entrance. Make sure that the entrances cannot be obstructed if the wrapping moves.
There is growing interest in an improved type of indoor wintering that uses a combination of supplemental heat, ventilation, insulation, and air conditioning to produce ideal wintering conditions. Single-story colonies established in late summer are held in complete darkness at 46-49 degrees F. (8-9 degrees C.) from about November to April. Food consumption is low, and the bees do not rear brood during the confinement period.
More honey bee colonies survive the winter and are stronger in the spring if they are routinely fed the antibiotic Fumidil-BÇ to control Nosema disease (see page 140). Each colony should be given 2 gallons of sugar syrup (2 parts sugar to I part water) containing the antibiotic.
Wind protection is important to good wintering. Shrubs, fences, or other artificial windbreaks help the colonies survive by slowing the loss of heat from the hives (Fig. 48). Snow may completely cover the hives without damaging the bees but the hives should not be located where water may collect. The winter apiary site should also be on a slope or in an area where cold air will flow away from the hives and not collect around them. If your winter apiary location does not permit the sun to shine on the hives or is undesirable in other ways for wintering, plan to move the bees to a better location.
Losses of bees during winter are often high in spite of increasing knowledge about the biology and management of honey bees. Many bees of all ages die in the hive. Losses appear to be greater in very large and very small colonies as compared with those of moderate size. It is not uncommon for more than half of the bees in a colony to die, and for 10 percent or more of the colonies to die. Starvation, either from lack of honey or from inability to reach the honey in extremely cold weather (cold starvation), is the most common cause of winter death of colonies.