I put some syrup on last week in a hive top feeder. I thought it would all be gone by this weekend, but they had stopped taking it. I boiled up some more not knowing that they were not taking it. I went ahead and added the warm syrup to that which I put put in last week. They immediately started into the feed. When I checked this afternoon (we have had a nice sunny day), the bees were busy accessing the feed. Foragers are still bringing in pollen in a steady stream. I am not sure what this means, but I am thinking it is a good thing.
If the weather is warm enough for the bees to get out they will usually find some source of pollen regardless the time of year.
When they stop taking the feed, is this when I remove the feeder an put a sugar candy board beneath an inner cover?
Yes, if they still lack adequate stores.