Through a UK winter a honeybee colony forms a tight cluster and slowly eats upward through the honey stored directly above it. It rarely breaks formation to search sideways for food — doing so in cold weather would chill and kill the outer bees. Colonies can starve with honey still in the hive simply because it sits out of the cluster's reach. This is why beekeepers judge stores by weight (hefting) rather than by opening the hive, and why an emergency block of fondant is placed in direct contact with the cluster rather than in a feeder the bees would have to walk to.
Many "starved" colonies found dead in spring are found with frames of untouched honey just centimetres from the cluster — the classic sign of isolation starvation rather than a genuine shortage of stores.
A cutaway hive shows a winter cluster eating a slow tunnel upward through its honey stores. Cold weather tightens the cluster and narrows its reach; a fondant candy board placed in direct contact keeps the colony fed even when it can't safely break formation to search sideways.
Colonies eat upward through comb directly above the cluster, not sideways across the hive. Below about -2°C bees rarely break cluster to shift to fresh comb, so honey elsewhere in the hive can become unreachable — a real cause of "starvation with stores in the box."
Set the outside temperature and how much honey the colony banked in autumn, then click "Advance 1 week" repeatedly to watch stores deplete and the cluster's contact point move. Toggle the fondant board on to see how emergency feeding rescues an isolated colony.
Beekeepers judge winter stores by hefting (lifting) the hive rather than opening it, precisely because opening a hive in cold weather can chill and kill the very bees it's meant to help.