518 IOWA DEPARTMENT OF AGRICULTURE 



If the wooden cover of the hive is loose or if the hive is covered with 

 some absorbent or porous material, the heat escaping from the cluster 

 may cause the formation of slight upward air currents which will carry 

 the moisture out the top in the form of vapor. Out of doors there may 

 be condensation of moisture in the porous packing more rapidly than it 

 can be carried off by evaporation, in which case the packing becomes wet 

 and usually thereby less effective as a non-conductor of heat. With sealed 

 covers the moisture must pass out the entrance and this may also occur 

 in the form of vapor if the outer air is of suflficiently low relative humidity 

 to take up all the water as it comes outside. 



One of the much discussed questions among beekeepers is whether it 

 is better to have the wooden cover of the hive sealed tightly by the bees 

 with propolis or whether the replacing of the cover with an absorbent 

 cushion to take up the moisture does not keep the colony in better con- 

 dition. The usual method of providing upward ventilation is to plac^ 

 several thicknesses of absorbent cloth or other absorbent material over 

 the frames, over which is placed suitable packing material. Out of doors 

 care must be taken to have the cover water proof so that the packing and 

 absorbent material will not become wet from rain or snow. Another 

 method used to a considerable extent in New York State is to have a small 

 hole in the front of the hive through which the moisture laden air may 

 escape. 



If the temperature of the inside of the hive, not in the cluster, is low 

 and the humidity of the air which escapes from the cluster is high, this 

 moisture will not escape from the entrance without condensation. In 

 such a combination of circumstances it is obviously advantageous to pro- 

 vide an avenue of escape. This the upward ventilation and absorbent 

 cover does. The late W. Z. Hutchinson, who had unexcelled opportunities 

 for studying bees in winter in North Michigan, says: "Those beekepers 

 who have been the most successful in wintering their bees out of doors 

 in the higher latitudes have, so far as I know, given upward ventilation 

 through some kind of packing material." Coggshall refers to the severe 

 winter of 1880 when in his region (Groton, N. Y.) the temperature re- 

 mained below 0.0° F. for three weeks in January. Three-fourths of the 

 bees in New York died and he lost half of his. Those saved had been 

 packed with burlap or carpet over the frames over which was four to 

 six inches of dry sawdust. Bees in box hives died unless the boxes had 

 a hole for flight half way up or were cracked so that moisture could 

 escape. 



On the other hand it is frequently observed that colonies in box hives 

 sealed inside by the bees often winter better than colonies in hives with 

 movable frames carefully packed. The majority of box hives are much 

 higher than they are wide. This enables the bees, by going toward the 

 top to keep the temperature of the combs about them high enough so that 

 moisture does not condense and furthermore there are frequently cracks 

 to allow the escape of moisture. 



In situations where the temperature of the combs and hive does not 

 often reach the point of condensation, or if a low temperature is prevented 

 by packing, a tightly sealed cover can do no harm and many beekeepers 



