I was very fortunate to attend the BCHPA Education Day in Kamloops this March 2017, and am looking forward to the Sat/Sun Education Day in Kelowna, BC in October.
I will report on two speakers (the second in another entry) only as the rest were speaking on Canadian honey labeling regulations.
Those regulations only apply to honey producers shipping across provincial/international borders, and/or selling in retail outlets. While hearing what is required was interesting, I do not fall into the regulated producer category.
The single point of interest to all was that in Canada, the label can say “Product of Canada” but can contain foreign sourced honeys (which as we all know are often not honey at all) as long as the final blend is blended in Canada. The label must also say that the honey is blended, and name the countries from which all the honeys in the blend originated, but that information is often in fine print and buried on the back label. Honey producers should fight hard to reform labeling information such that consumers can more easily understand what they are buying.
Speaker Notes: Rudi Peters
Rudi presented on his researches into overwintering in Terrace, BC. While Terrace is much farther north than we are, Rudi feels his biozone is, thanks to warming ocean currents, similar to ours here on the border/WA state coastal area.
Rudi’s goal was increasing winter survival of his colonies. When he has experienced overwintering failures it has always been due to starvation (he controls diligently for Varroa mites using formic acid and oxalic acid). Typically his overwintering rate is 90% or better, and in his worst recent year, rates were 73% in one of his two yards. That year of 73% was due to an unusually hard and long winter season which included 7 weeks of hard cold caused by an arctic outflow. Typical winters offer only one week of hard cold.
Rudi feels his overwintering success is dependent on supporting the bees’ ability to maintain consistent internal environmental conditions. To clarify, he first carefully defined three terms that are often used interchangeably, the confusion of which muddies discussion of overwintering technique:
- humidity = the % value of water vapour in the air
- condensation = when water vapour becomes liquid water
- moisture = liquid water, either diffused in a solid or condensed on a surface
Rudi emphasized that it is condensation dripping down onto bees from a cold inner cover that is the winter colony killer. Humidity and moisture do not kill bees, but condensation can.
He noted that his Italian colonies did not overwinter well, but his Carniolans and Russian crosses did. He noted that the latter are diligent in propolizing shut all cracks and entrances in fall, leaving only tiny entrances. That got him thinking.
Placing temperature sensors in hives, Rudi noted that unwrapped and uninsulated hives placed to receive max sunlight in day experienced extreme temperature swings between day and night…up to 20 degree C swings. The effect of these swings was that the cluster expanded greatly in the daytime, but contracted sharply at night, causing brood laid outside the night cluster area to chill and die.
This progressive egg/larvae loss intensified the effect of normal winter attrition in the older bees, ie. young bees were coming along at a reduced rate, compromising the ability of the colony to maintain critical late winter cluster size. He also felt the winter bees were dying at an increased rate.
Rudi experimented and settled on the use of Reflectix insulated wrap to smooth out interior temperature swings:
According to the manufacturer:
“Reflectix is a 5/16-Inch thick, seven layer, reflective insulation which is available in rolls of various widths and lengths. It is used extensively in both specialty and standard construction projects. Two outer layers of aluminum foil reflect 97-Percent of radiant heat. Each layer of foil is bonded to a tough layer of polyethylene for strength. Two inner layers of insulating bubbles resist conductive heat flow, while a center layer of polyethylene gives Reflectix high reliability and strength.”
The winter configuration used was a single deep, filled with bees and stores, under an inner cover. Over the inner cover (which has a central hole and provides NO upper entrance) goes an empty medium super with screened vent holes drilled in its sides. Into that vented super is placed a single layer of Reflectix, topped by a quilt pillow (making this a minimally ventilated quilt box over the inner cover, as for the most part the layer of Reflectix blocks significant air flow out of the centre hole in the inner cover). Rudi’s quilt pillow is R20 pink insulation batt material sealed in a clear poly envelope. The quilt box is topped by the insulated roof/outer cover. The entire stack is wrapped in Reflectix, to be unwrapped in March (when days start to average over 10C). photos at end of entry
Rudi also examined the effect of having an upper entrance in winter. Upper entrances are standard practice in deep snow areas, not only to permit cleansing flights, but a perceived necessity everywhere in venting moist, humid air from the hive (in particular to prevent condensation on the inner cover). Note that where Rudi uses only bottom entrances, he keeps the entrance clear of snow.
Examination of hive sensor data revealed that colonies with upper entrances experienced *higher* humidity and more extreme temperature swings that hives without upper entrances. Hives with no upper entrance had more constant interior temperature and, *when a quilt box was added and the roof heavily insulated*, experienced no condensation on the inner cover above the cluster.
Not what we expect! Presumably the upper entrance increased the flow of cold air into the bottom of the hive (as warm air vented out the upper entrance), forcing the bees to push up their metabolic activity to compensate, which succeeds in generating replacement warmth but as a consequence increases the amount of water vapour coming off the (more active) cluster.
The increased metabolic rate required to overcome loss of heat through an open upper entrance may also explain Rudi’s sense that the winter bees were dying at increased rates. They may just have worked harder, shortening their lives. They may also have been more vulnerable to chilling when on the outside of the cluster in a draughty hive.
Tracking hive weights revealed that colonies with no upper entrance, wrapped and with insulated tops consumed fewer stores in winter (preventing starvation during cold spells), and more of their stores in later winter/spring. Because they conserved stores, they were able to use those stores to make baby bees in late winter/spring rather than to generate heat calories in winter.
The result of this configuration (no upper entrance, quilt box, heavily insulated roof, wrapped stack) was that colonies arrived in spring with an average of 3 to 4 more frames of brood. That allowed a larger April colony, giving the beekeeper better options for colony management.
All photos below credit to Rudi Peters, Skeena Valley Apiary.