The first swarm of the season contains the old queen who will be
replaced after they get settled in their new home.
Swarms after that will have young queens produced that spring.
Most swarms are gentle the first few days they cluster on a branch but
when they run short of food get a little testy.
A beekeeper will generally knock them into a box or bucket or get them
to march into a hive box with drawn combs. Around here folks think I
am some kind of wizard because the last time they watched me hive a
swarm I was in a t shirt and flip flops and knocked them into a copy
paper box.
In an area with known africanized honey bees it is better to err on
the side of caution, they move along in a few days without being
hassled.
Africanized honey bees are nothing special they just have not had
their defensive qualities bred out of them yet. The same idiots who
call a foot of snow the storm of the century will hype them as "killer
bees" to make sure they can sell enough advertising.