I’m typing these words on the shortest day of the year. You’ll often read that colony broodrearing and buildup are triggered by the winter solstice, but there is little supportive evidence for that claim. Instead, it’s been clearly shown that winter-bound colonies typically resume a small degree of broodrearing even as the days are getting shorter in December. And if weather conditions and bloom are such that there is a nectar and pollen flow over the Winter Solstice (as often occurs in Australia, Southern California, and Mexico) colonies will be rearing brood like crazy on the shortest day of the year. And they will even brood up midwinter if held at constant temperature in total darkness in a wintering shed.
Based upon a couple of interesting studies by Dr. John Kefuss, it appears that bees may be more responsive to the daily change in day length, rather than the number of minutes of day length itself. Here in Grass Valley, there will be no detectable change in day length the day following the Winter Solstice, but a full 3 minutes per day change at the Spring Equinox. Up in Canada, the daily change at that time may be up to 5 minutes. This could be one reason why colonies grow so much more rapidly at high latitudes.
Anyway, as far as bees in Nevada County, their spring buildup is usually triggered by the availability of the first alder pollen. The catkins on the alders are now fully developed, and I expect them to begin producing pollen perhaps the first week of January (alders are indeed triggered by photo period). If we get good flight weather during this bloom, our colonies will start ramping up broodrearing with vigor. But be aware that such an early ramp up will result in two things: (1) early swarming, and (2) an early start to varroa buildup.
So far, this winter has been unusually warm, with very few frosty nights until recently. Warm winter days without enough pollen to stimulate broodrearing, may tend to wear the bees out as they engage in “fruitless foraging.” But unless it is rearing brood, the colony has no means for replacing those worn-out foragers. We were concerned about that, and fed a thousand pollen patties this week to encourage the colonies to engage in a bit of broodrearing, in order to have strong colonies for almonds. We applied our winter dribble of oxalic acid to control varroa at the same time.
On that subject, we’re trying a different dribble formulation this season. Based up research and practical experience in Europe, beekeepers are switching to glycerin, rather than sugar, as the humectant in the dribble. I’ll go into more details after we’ve seen the results this spring.
We’ve noticed that during this warm weather, a number of colonies have gone through their honey more quickly than expected. It would be wise to heft your hives in order to confirm that they’re still heavy.
Grass Valley, CA