A recent article in American Bee Journal stated that average yearly losses prior to varroa and tracheal mites was about 30%; some years more and some years less. Most beekeepers run extra hives to compensate for these losses. I suspect the average loss is slightly higher now with the mites. The warm weather in the last week has allowed some beekeepers the opportunity to assess the conditions in their apiaries. Here are reports from fellow amateur beekeepers (both club members and non-members) about their winter losses.
Beekeeper Fred (member) reported the following. As of today Fred has lost 4 of 29 hives (14% loss). Fred runs a mix of Russians, Italians, Carniolans. Fred had wrapped about half of his hives in BeeCozies. All hives were inspected and graded in the fall as "Strong", "Normal" or "Weak". Some, but not all, hives had received fall feeding. All hives were treated with formic acid (half strength on Russian hives; full strength on the others). Most were also provided winter emergency food in the form of sugar patties on the top frames. Two of the four lost hives were hives that had gone queenless sometime in August. They had been requeened with Russian hybrid queens in September. These 2 hives had been rated as "weak" during fall inspection and did not quickly consume the fall feeding offered. The third was a Russian hybrid hive that was classed as "weak" at the fall inspection. The fourth was an Italian hive which had been classed as 'Normal" during inspection. This hive had NOT been offered fall feeding. To date, the data shows no measurable advantage to wrapping the hives; 3 of the 4 lost hives had been wrapped.
Beekeeper Denise (club member) reported the following: As of today Denise has lost one of four hives (25% loss). Analysis of the hive indicates it died of starvation. This hive had filled four supers with honey last summer, but did not have enough to winter over. The three (3) remaining hives appear to have nosema, but are living. Denise will be treating with fumigilin to try to control it. Denise treats her hives with a thymol based pesticide in the fall.
Beekeeper Jon (non-member) reported the following: As of today Jon has lost 3 of 20 hives (15% loss). Jon runs VSH Italian bees in most of his hives with a few Carniolans. Jon also had both a fall and winter feeding program. 2/1 sugar water was offered in the fall after honey removal. Sugar patties on the top frames were provided in the winter as emergency stores for the bees. Jon does no chemical treatments for mite control. Jon's notes and analysis of his lost hives showed: one hive robbed out in late fall; one hive had nosema/dysentery, and the third failed due to starvation. The third hive was a single deep combined with a nuc in late fall. There was insufficient honey/sugar in the second new deep to carry the hive all the way through winter. Some beekeepers would have culled this hive in the fall.
Reports of heavy losses of other non-member beekeepers have been heard third hand.
There is still a month to go before tree pollen normally becomes available.
Bring your apiary winter results to the March club meeting.
Thanks to Jon, Denise and Fred for their inputs.