In the past, bees stored enough feed, in the form of pollen and honey, for their own year-round use and usually stored a surplus for the beekeeper to harvest. However modern agricultural and apicultural practices often require that bees be fed. Bees prefer to consume nectar and their own honey, so the consumption of feed (sugar syrup) indicates a lack of these. While being fed, bees will consume some feed and store some. The rate the feeder is being emptied provides only partial information. Correlating feed data with hive weight data and brood volume data may be helpful.
Electronic feed monitoring devices
At this time we are unaware of any electronic feed monitoring devices. The simplest such device would report when the feeder is empty. A more sophisticated device would report the rate feed is being taken from the feeder.
Manual feed monitoring
Manual recording of feed consumption data is the current option. Beekeepers may note the date the feeder is filled, the amount of feed, and the date the feeder is found empty. If a container with graduated marks to indicate the quantity consumed is used, a more detailed record of consumption can be recorded. If bees are not taking feed as expected, the feed may have gone bad, or a nectar flow may have started.
If it is cold, it may be too cold for the bees to break cluster and reach the needed feed. Ensuring that over-wintering colonies can occasionally warm up naturally and the bees can break cluster to reach stores of honey or syrup is vital to colony survival. Measuring hive weight changes and feed consumption rates is one way to determine whether colonies have been configured so as to enable successful overwintering.