Catching swarms is a chance to grab healthy, happy bees for free at a time of year just as the nectar flow approaches. People are grateful to have someone deal with this natural but unfamiliar phenomenon, while saving the bees and having a really cool experience. Here's how to prep for the job.
Item 1: Information
The first thing you need when catching a swarm is some idea of how to do it. Start by learning to be a beekeeper! Swarm collection is NOT for non-beekeepers, and will result in harm to the bees (and maybe a few stings for the brave-but-foolhardy).
If you are already a beekeeper, helping someone out who has done it before is your get-started-fast approach. We also recommend a great book and easy read, Swarm Essentials.
Item 2: Protective Gear
Bring a veil and gloves, wear closed shoes and socks, tuck your jeans into those socks. You are likely to make it rain a few bees at some point. Everyone is happier when they are on the outside looking in. By the way, as soon as you put that veil on, this becomes a public event. Make sure you have this stuff, but don't put it on until you are ready to rock and the location is secure (i.e. all those curious people have stepped back)
Item 3: Honey Bee Collection Container
Copier Paper Boxes make excellent swarm catchers: they are widely available, free, portable, breatheable, the right size for a small branch to be dropped in, and their telescoping cover makes it easy to keep it open a crack while the bees fly in—and then to gently seal them in for the ride home. Those office moving boxes with the hand holds in the sides work, too (and are a bit larger) but you have to tape the holes shut and they are bulky to hold up under a cluster.
Also: you can probably fit all of your swarm kit tools into this box!
Item 4: Piece of Cloth
Bring an old bed sheet (preferably full or queen sized or bigger) or a non-plastic drop cloth for two reasons: to spread on the area underneath the swarm in order to catch clumps of bees that become dislodged from the main group (so you don't stomp them or have to chase them later, and can rest assured that the queen isn't running around on the ground somewhere) and to wrap around your box once you get it in the car (in case of leaking bees). You can purchase canvas drop cloths from paint stores, but should give them a good wash or two before using. At some business locations, you can request and borrow a tablecloth in a pinch.
Item 5: Spray Bottle filled with 1:1 Sugar Water
To reduce flight and accentuate the clumpiness of a swarm, you can wet them down with a gentle spray of sugar water on all sides. Soaked bees are not the goal: you will not be able to dislodge them with your brush if they are too wet. It's important to get a strong sprayer that holds a lot (like 32 oz.)—not the cute cosmetologist kind. Garden stores have OK ones, but the chemically resistant ones used by cleaning companies that are available at major hardware stores can handle thicker solutions and last longer.
Item 6: Bee Brush
We all know that bees hate the brush, but you will use it to usher those last few on the outside of the box in, and to try to encourage the last stragglers off the trunk of shrubs, etc. Make sure your brush is washed, dried and soft. After using it for a swarm, it can dry to a candy-crusted texture, which kills bees.
Item 7: Pruning Shears (the little ones)
Sometimes you get a "convenience" swarm", where all the bees are hanging from a little branch you can nip off into the box. Sweet. But sometimes you just need those shears to trim off little branches that stick into your swarm so you can shake it free. You don't always need shears, but they sometimes save the day.
Special Situation Items: Ladders, Bee Vacs, extension poles, buckets, pruning hooks, bucket trucks, etc.
There are swarms where the main problem is access— they are too high, in too gnarly a setting (like a chain link fence), and so on. Most of the time you should let these go: the going rate this year for packaged bees averages less than $100, and ER visits are much more. But if you can't resist, we suggest that instead of trying to include these items in your go-kit, that you create a list of people who offer these items, and their email and phone numbers. If you decide to go for it, you can then call in your peeps.