Trapping swarms is one of the key management techniques practiced
by beekeepers in South Africa, and Africa. As said in some of the other
replies, you need swarms. So you need to put the trap boxes in the
right location. During the autumn in South Africa, for example, if you go
on a trapping expedition to the commercial eucalyptus grandis forests,
you can catch hundreds upon hundreds of swarms in a few months.

The approach to optimum trap boxes hinges on age of furniture, and
scenting. Use the oldest hives available, and the oldest frames.
Supply the frames with strip foundation of about an inch. The next part,
for beeswax and propolis, is critical. Using a paintbrush, paint the
inside of the hive and around the entrance with molten beeswax
(molten beeswax goes a long, long way). Then take about five warm,
peanut sized pieces of propolis and massage these to make contact
with the hive entrance. Then, and again, this is critical, blast the
propolis (but not into oblivion) with a plumber's gas torch. If you have
more propolis, do the same thing at the top four corners of the hive
(with the lid off).

If you are in a location with prolific swarms, you can replace some of
the strip foundation frames with frames with comb.

If you can place the hives on permanent buildings, place them at
corners of the roof, preferably facing east (west in the northern
hemisphere). If you place them in trees, they should be at least eight
foot off the ground.

For scutellata, we also use very low cost plastic trap boxes that hold
five old brood frames. You can see pictures of these at:

http://www.algonet.se/~beeman/

Click on pictures, South Africa, etc. The catch box you see with bees in
occupation was randomly selected by the bees. Nearby, there were
empty ten-frame wooden hives, but the bees wanted the plastic one. It
was about three feet off the ground. Now, don't ask me to explain that!
In the commercial forests, a really big swarm will settle on one of
these plastic catch boxes. But, because the swarm is so big, the bees
build comb on the outside of the box, ignoring the interior. In due
course, they issue swarms that hopefully occupy the interior of other
plastic catch boxes. We often place these catch boxes in contiguous
lines of 100. After trapping a swarm, you should wait a minimum of
two weeks before transferring the bees and frames to a new location
and proper hive.

Barry Sergeant
Kyalami
South Africa