Natural honey bee hives in hollow trees often have multiple entrances. Bees fly in and out of knot holes or broken openings linked to the tree’s cavity. I watched a colony of honey bees in a sweet gum tree for four years. The bees entered the hive through a hole in the tree near the ground. At times, the bees also used a second entrance, a knot hole three feet above and to the side of the tree. The bees would use the upper entrance for awhile, and then seal it with propolis. Eventually, the honey bee colony swarmed and settled into a wood duck nesting box about the size of a deep bee hive body. The duck box had a large entrance hole near the top, facing east. The bees survived a winter in the duck box, and I hived them the next spring as my first managed colony.
Honey bees readily use holes in rotted corners of beehives as extra entrances to the hive. The late George Imirie designed shims with openings to give bees an upper hive entrance. See http://www.tnbeekeepers.org/learning.htm, and then “George Imirie” and “Optimizing Honey Production.” The blue-colored Imirie shim shown in today’s photo allows foraging workers to enter the honey supers without passing through the hive’s brood nest. Imirie felt that using upper entrances with frames of drawn comb increased his honey production. Adding an upper hive entrance also increases ventilation through the hive. Jerry Hayes conducted a small-scale investigation into the effect of upper entrances to bee hives. The report can be viewed at http://www.beesource.com/point-of-view/jerry-hayes/queen-excluder-or-honey-excluder/. Hayes compared three configurations of bee hives: control hives with entrances at the bottom and no queen excluder, hives with entrances at the bottom and a queen excluder, and hives with an upper entrance above a queen excluder. The hives with upper entrances outperformed the other hives in two ways: There was less brood chamber congestion from honey, and more surplus honey was stored in the honey supers.--Richard