Re: 50 % Hives lost this Winter
I am just starting out and have done a ton of reading and learning. My comments are mainly a way to look at problems others have and then say what I see in it. Largely for the opportunity of others to correct my thinking.
One problem I see in general and not just about this thread. Words like "Strong hive" are subjective. In this case a number is then given. 30 lbs of honey. Now i respect the fact that you think a 30 lb hive is a strong hive. But I wouldn't. Next fall if my hies do not have a minimum of 50 lbs of honey in them I will expect to have a battle on my hands and still expect to loose it. I might even combine two hive and have more like 75 to 100 lbs of honey on it just to prevent losing bees.
In your case even your 30 lbs of honey is not gone though. My next thought was. Did they have water? Did they forage during the warm periods and then get caught out in the cold?
Nothing left in your hive indicates strong. The bees went somewhere. I am also wondering if they simply absconded?
SO here is my best guess, Just like you shooting from the hip. Bees foraged during warm periods with many getting caught out in the cold. No clean up necessary as the bees that died died in the field. as the hive population dwindled the bees may have realized there plight and taken measures to fix it themselves by eventually absconding (absence of queens) either some bees got left behind or the foragers that had been caught out in the cold but survived returned to the hive after the others where gone and this accounts for the small dead clusters you do have.
One other observation. I don't see the number of bees in any of your photos that says strong hive. This means you are right and in fact a strong hive was made very weak in short order. Or your idea of a strong hive is off the mark a little bit.
This year with the warm and cold cycles I would have been on guard to help any hive through. Warm weather in the months that are supposed to be cold simply rings an alarm for me. Bees will be active and eating when there are no replacements available.
Sorry to here of such heavy losses though. Hope it results in some answers for you. It reminds me of a saying. The school of hard knocks is a great teacher, but the tuition is very steep.
Watch the population of your other hives. I have no idea what you can do to keep them from foraging when they will just be caught out in killing cold at night. I have seen information that indicates that lots, even hundreds of foragers do not make it back to the hive each day. The most telling was a recent post that someone had placed sugar water in a swarm trap. this attracted foraging bees in droves. that night there was 2 to 3 hundred bees camped out in that trap that never returned to their hive. Now think of a half dozen locations your bees may have been foraging and that 2 to 3 hundred got left out each night at each location. it is not hard to imagine a strong hive dwindling very quickly with those sort of losses.
The 50 percent you lost might be colonies that tended to forage later in the day as well. I don't think I am really painting the correct picture at all, but the pieces fit.
Originally Posted by okbees
Significant Minority vs Insignificant Majority, 20% of causes produce 80% of the effects.