My new toy is a Flir-one thermal imaging camera. I wondered whether heat from the bees would be visible, providing a way of checking on affairs in the hive without opening it in winter.
So, as soon as the new camera was up and running, I ventured out into the cold December night. At first, pointing it at the hives on the gin terrace, I couldn't see any particular heat signal. But it might have been masked by these hives being right next to the house and having lots of heat "pollution" around them. Then I had the idea of putting the camera under the hive, which has an open mesh floor. This is what the camera saw in the Disc hive:
These images are taken looking up through the mesh floor at the underside of a row of honey frames hanging in the super. Above the super is the brood box where the bees are spending the winter. There appears to be a glow coming from above, so perhaps that is heat shining down from a cluster of bees in the brood box?
Although I couldn't get a signal from the Cedar hive (right next to the house, perhaps too much background radiation), things looked similar in the Copper hive and Pond hive:
The Copper hive and Pond hive broodboxes also look warmer than other parts of the garden when viewed from the outside:
The garden pond - that pool of molten lava to the left of the Copper hive - looks warm too.
I can't be certain that the bright glow in these images is really heat generated by the bees...it could just represent the thermal mass of the hive, which has heated up during the day and is now cooling down, just like the garden pond. A cold night in March or April would probably be the best time to see the bees making a difference, because we still get sub-zero nights then but the bees will be working hard to maintain a high temperature for brood rearing. At the present time of year the colonies may only be ticking over, clustered against the cold.