Quote Originally Posted by psfred View Post
snip
They simply cannot use the sugar above the inner cover when it's below 45 F inside the hive, since they will be clustered and won't be in contact with it. When the feed is sitting on the top bars, they can cluster ON it, and feed from it while still clustered. Much better.

Bees will cheerfully eat fondant, dry sugar, sugar bricks, whatever up on the top of the inner cover any time it's warm enough for them to move there, but they really need it accessible when clustered if they are that short on stores.

Peter
Update:

I visited most of my hives today, placing a little (insurance) fondant on some nucs, and checking for losses.

One particular colony had a prepared "SugarBag" placed on it last month... And, in spite of the cold (28F) bees were active up inside the bag of sugar. I don't know if the temperature inside the hive could have been 45.

I had rinsed off my hive tool before checking on the "SugarBag" and packing up. When I was finally ready to leave ice had started to form on the wet hive tool...

So... I have bees feeding in a bag of sugar (on the inner cover) when ice will form on a wet hive tool.