In discussion of winter losses, one always bear in mind the condition of the colonies in the fall. If these are not equal, then the resulting winter losses cannot be reasonably compared. It is like a race where everyone is starting at a different time.

> A colony population of adequate strength for winter is a prime requisite. At the close of brood rearing in November, a colony of suitable population should fill at least two standard 10-frame hive bodies from wall to wall and top to bottom at a cluster ing temperature of about 40° F (4.44° C). Smaller colonies should be united, and only first-class colonies should be overwintered. A poor policy is to attempt to overwinter subnormal or weak colonies, because they seldom will survive. The potential winter loss is best taken at the start of overwintering to keep the equipment clean and conserve honey. In the spring, strong, overwintered colonies can easily be divided and colony numbers doubled or trebled. The age of the bees going into winter is as important as population size.

> A full-strength colony of honey bees in most of the northern tier of States and in Canada will require no less than 90 to 100 lb (41 to 46 kg) of honey stores to survive from October to April. The average colony of bees in this area will consume about 60 lb (27 kg) of honey during this period. Some colonies may use only 20 to 25 lb (9 to 12 kg), whereas the better class of colonies will use up to 80 lb (36.3 kg). To insure survival of the stronger colonies, with a margin of extra honey for insurance, 90 to 100 lb (41 to 46 kg) of honey should be left. The gross weight of a 3-story colony in 9-1/2-in (24.1 cm) 10-frame equipment should be no less than 175 lb (80 kg) in October. Strong colonies will usually consume considerably more honey over winter than weak colonies.

> A colony prevented from rearing a normal amount of brood in late summer and fall (because of crowding or queenlessness) may look populous enough in early winter. However, such a colony will be comprised mostly of older bees. They will die early in winter, which results in a small population later on. A sublethal dose of insecticide in late summer or fall may also reduce bee longevity or disrupt normal brood rearing. Another major cause of winter loss is lack of wind protection. Colonies in exposed, windy locations will quickly become weaker because bees at the periphery chill, drop, and may eventually starve as the populations no longer can cover adequate stores. Expected winter losses, when all requirements for good overwintering are met, should be about 1 to 3 percent of the colonies overwintered, and in many years can be nonexistent.

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