Winter Losses?

[Podilia]

It's my first winter (with 2 colonies) and there are snowcaps on the hives, so thanks for the advice about that. I last checked the food on 1st Jan and there were about 2kg of fondant left on each. I'm in the habit of listening with a stethoscope and usually there's a quiet hum - today, nothing, or nothing that I can hear. What's your experience of listening in? Have you found some days with no detectable hum?

I can say that when there is a low temperature (for example -5-10) bees buzz louder. If warmer - sounds decrease and not so clear. I use just a piece of a rubber tube 1 cm of diameter. If you hear nothing knock slightly the hive. They should respond. If they quickly become calm (a few seconds) there is probably a starvation. The sound of hungry bees is like dry leaves. But more practice is needed to identify it. If you are not sure better open and observe the colony.