An all to familiar sight this time of year. A queen with a handful of bees and no brood or a few eggs.
Those finding hives empty of bees and brood will have witnessed the end result of dwindling ie. dwindled to nothing.
What I did with this colony was:
1. Put the queen in a queen cage and then into my shirt pocket to keep warm.
2. Get my mini nuc (always have a couple ready to go with starter strips and fondant in a plastic bag) and go to healthily hive and shake the recommended amount of Nurse Bees into the nuc (see instruction for your model).
3. Take mini nuc and Queen in cage home and approx 2hrs later add Q to the mini nuc
4. Keep in shed overnight then put the mini nuc in garden and open entrance. I leave the Q excluder over the entrance for a few days to stop queenie flying off.
5. Check 2-3 weeks later and if combs being drawn and queen laying and worker brood cappings then the queen can be introduced into a nuc or full sized colony.
It's important to only use young bees to make up the nuc otherwise the Q may be killed.
It's the queen that is worth saving from the dwindling colony as the bees and or comb may be diseased.