The Cycle of the Year 
89 
animals while the conservation of heat depends chiefly on 
the structure of the winter cluster. 
When the last brood has emerged, the colony and its 
nest are then in condition to pass the winter. In cold 
weather the bees form a single compact cluster and leave 
the hive only on occasional warm days for cleansing flights. 
Bees do not discharge their feces in the hive so long as they 
are in normal, healthy condition but, after even a short 
confinement, will venture out for this purpose as soon as 
the outside temperature permits. 1 
Movements in winter. 
The cluster is first normally formed where the last brood 
emerged; here the bees find empty cells into which to 
crawl, so that they form themselves into a compact mass, 
separated only by thin walls of wax. They do not form 
the winter cluster where the combs are filled with honey 
and it would probably be impossible for them to conserve 
the heat of the cluster if sheets of honey separated the bees 
in adjacent spaces. As the contiguous stores are consumed 
and additional cells are emptied, the cluster is shifted so 
that the bees are always near stores. This shifting is, how¬ 
ever, apparently impossible in extreme cold weather, when 
colonies sometimes die in a way that can be explained only 
as due to starvation through inability to reach stores just 
a few inches distant. The early fall cluster is usually low 
on the combs, near the entrance, if there is considerable 
honey stored and the movement of the cluster is usually 
upward and toward the rear of the hive as winter progresses, 
and as stores are consumed. If a colony is in a two-story 
hive, the cluster is often in the upper story in the spring. 
Responses to outside temperature. 
The cluster varies in size with the outside temperature. 
After the emergence of the last brood in the fall, if the 
1 Bees often remain in the hive at a temperature of 70° F. if a flight is 
not necessary, but will often fly when the temperature is about 50° F. if 
they have been confined for a time. 
