This past Tuesday I caught a swarm (from my hive). The bees entered the swarm box this past Tuesday, but yesterday many of them left the box and bunched up in the tree where the box is, about 20 feet away. The weather has been rather rainy and cool, but today the rain stopped, and it was sunny and about 85 degrees. For whatever reason the bees returned the swarm box. Traffic in and out of the box is heavy, with a good bit of pollen being brought in.
I would like to screen these bees in tonight, but the weather report is for rain for the next 2 days. I have never kept bees screened in for 2 or 3 days, but may be faced with that possibility in this instance.
I would appreciate comments, pro or con about doing this.
You don't need to screen them in - I'm not sure why you would want to. If they've gone out and come back in, I'm betting the queen is in there and they've settled on your box as their new home.
Do want to screen them in just so you can safely move them? I'd screen them in and move them in the rain tomorrow, then unscreen them at the new location, but leave them in the trap. You can transfer them to their new boxes when the rain stops.
If you want them to stay and have the resources to do it, pop in a frame with some brood on it. This is a very effective anchor, but it gives up one of the advantages of a swarm which is that you have a brood break with the possibility of a quick one-shot of OAV to clean up any mites they may brought along with them.
OTOH, if you don't use OAV, then there is nothing lost, particularly if you already know the treatment history of these bees.
The one time I had a swarm from a new colony in my yard, I got them out of the tree with much effort and drama, and gave them a frame of brood from the parent hive. I've often wondered what they made of that. They go through the whole process of swarming, wind up in boxes with undrawn combs, except for a frame that smells exactly like the ones they worked on in the hours before they left.
The weather report is for showers and thunderstorms starting sometime tomorrow morning through Sunday and ending Monday. The bees' behavior of leaving and hanging out on the tree has me a bit concerned that they might just bolt.
If the rain holds off tomorrow morning I will put into a hive tomorrow morning and add a medium super to give them extra room. I guess if the rain is pouring tomorrow morning I will remove the screen and let them stay put.