Snowdrops, and other early flowering bulbs such as winter aconites and then crocuses are some of the first flowers of the year. At this time of year, hopefully your bees are not starving but they will be surviving on mainly on honey or fondant for a while which is pure carbohydrate. To start healthy growth of brood numbers they will need the protein that comes from pollen. These small flowers may take a time to bulk up and provide a plentiful feast for the bees but at this time of year small quantities of pollen are just enough to give them a bit of a boost until the rest of the spring flowers bloom.
Other very important group of plants that might begin to flower in February is the trees. As the blossom begins - particularly the willows with their catkins - they will soon become the main food supply for all bees in spring.
If you have wallflowers planted in a previous years, they may also begin to flower from February, depending on the variety. The native wallflower; cheiranthus cheirii, tends to be an early flowerer but I have also known Bowles Mauve, another reliable wallflower for bees, flower now too.