Spring Feeding: A worthwhile activity?

There is a lot of information about feeding bees available - after all, starvation is one of the biggest killers of bees through the winter months. Almost all beekeepers would agree that it is (sometimes) necessary to feed bees thick syrup (2 parts sugar, 1 part water) and/or hard candy or fondant in late Autumn, to boost the stores already laid down and see them through to the spring.

However there are a number of sources which also advocate feeding a 'light' (1:1) syrup in the spring - to boost colony buildup, increase brood rearing, and set the bees up for a better start to the season. However does this actually make a difference?

There have been several studies which show that this act of feeding is at the very least inconsistent in it's effects, and possibly detrimental to the colony.

Free and Spencer-Booth (1) found that:

Feeding dilute or concentrated syrup increased brood rearing during and after feeding in one year (bad weather) but had no effect on brood rearing in the other year (good weather).

Butler (2) notes that:

feeding dilute syrup throughout March and April did not affect brood rearing but feeding concentrated syrup significantly decreased it.

Randy Oliver (3) discovered that there is no 'mutliplier effect' from feeding - that is, feeding doesn't in turn encourage greater foraging. In fact, colony weights decrease less than the quantity of stores given - for every 3lbs of syrup provided, the colony mass increased by only 2lbs.

Michael Bush (4) has also collected a number of quotes from famous beekeepers dismissing the effect of stimulative feeding on brood rearing.

Feeding can also have negative effects. Firstly, if fed in excess it forces a potentially weak colony to put effort into processing nectar - storing wet stores will chill the hive and increase humidity, making brood rearing more difficult. Storing excess syrup could also lead to a hive becoming honey bound. If it does encourage brood rearing (and the jury seems to still be out on that one!) it may cause the bees to increase the brood nest size beyond that which they can manage, and a sudden cold snap, or an absence of feed (if you forget to keep feeding them!) will cause chilled brood and place undue stress on the colony.

So is there any point to spring feeding? Well, as noted above, it is of benefit in poor seasons - presumably for the simple fact that otherwise the bees will not be able to forage and will fail to build up at all due to a lack of stores (though it is not necessary in good years, or for colonies with high levels of stores remaining from winter). Feeding bees is always better than letting them starve!

It is also of benefit to feed if there is a desire to draw out foundation rapidly. An excess of food encourages wax production in nurse bees, so combining feeding with the addition of undrawn frames can be a good way to get them drawn out without adding additional strain on the colony's resources.

Additionally, there is some evidence that feed additives can have a beneficial effect on brood rearing. For example, Mărghitaş (5) found that certain additives - in particular nettle extract, has a positive effect on buildup as part of a spring feed.

If you do decide to feed, it should only take place when the daily temperature rises regularly above 10C. Below this, and the bees will ignore cold syrup, and it will just act as a heat-sink on top of the hive. Follow the mantra of 'little and often' to prevent the problems of excess highlighted above.

And if you decide not to feed in the spring as a matter of course, remember that you still need to ensure they have enough stores going into winter, and heft your hives from time to time going into spring and be prepared to feed to fend off starvation!

References

  1. Free, J. B., and Yvette Spencer-Booth. "The effect of feeding sugar syrup to honey-bee colonies." The Journal of Agricultural Science 57,
    no. 2 (1961): 147-151.
  2. The provision of supplementary food to hive bees
  3. Scientific Beekeeping: Is there a multiplier effect from the feeding of sugar syrup?
  4. Bush Farms: Feeding Bees
  5. The Effect of Plant Supplements on the Development of
    Artificially Weakened Bee Families