We are having a few nice warm days. For hives in the direct sun the bees are out doing voiding flights. Did you notice all the gold spots in the snow? Some hives may not be flying. Some of mine wrapped with Bee Cozies are not flying. I assume the Bee Cozy is insulting the hive from the warming effects of the sun.
Also although your hives may have lots of flight activity they are NOT getting ready to swarm. This is because swarming requires four things; none of which exist right now.
1) Large population
2) A replacement queen being raised
3) Drones available to mate with the queen
4) A strong pollen and honey flow.