It would appear that the hive which I put Colony 10 into didn't suit them. I checked this morning and they've left.

This isn't a big surprise. Swarms can be actively looking for sites even after they're put into hives. I did open the hive the day after I put them in and saw them mostly stuck to the hive wall. That suggested that they hadn't accepted the hive. I don't know why they didn't like it.

This morning there were 3 or 4 groggy and cold bees still there but it was otherwise empty. I think they may be scouts which were still out when the swarm left.

For at least the last 2 years there have been flightless bees crawling around outside Hive A. These bees were clearly suffering from Deformed Wing Virus or another disabling virus. This year there are none.

The cause was explained to me by a researcher at University of Salford. All winter the Varroa mites feed from worker bees. They accumulate DWV virus particles. In spring, when brood production increases they rush in to infest the new brood and transfer more virus to them. These bees show visible signs of DWV -- deformed wings or an inability to fly.

I was called today at about 5pm about a swarm in Barton. It's from a feral colony which I've caught from before and they seem pretty robust. They've been feral and untreated for at least 3 years.