Overwintering Drones

[Jon]

This colony had drones flying in late November and still has drones in March.
I checked records and I have not seen the queen since the end of July although it did have normal worker brood in September.
I wonder what is going on. It is very strong and active.
The temperature today is 9C
I notice there are a couple of workers with K-wing.
It was treated with Apiguard in August, Oxalic late December and got fed some thymolated sugar syrup in the autumn.
I need to get a look as soon as the weather gets slightly warmer.

[Jon]

I quickly checked this one at lunchtime today.
I carefully lifted one frame from the middle of the cluster. It had normal worker brood and by happy chance the marked queen was on it.
The colony was over about 8 frames so is a strong colony for the time of year for a native type bee.