Lionel,
Having gone though references at my disposal, it seems that bees have a
tendency to build natural comb at an angle of 50° from magnetic north -
i.e. in a N.E. - S.W. direction
Apparently the angle varies according to the species of bee.

I have never measured this activity myself,
- but will throw in that for my bees, the direction that a swarm leaves
the hive and clusters is more often than not in the western sector -
helping to find those that are hanging in dense bushes/ woodland
adjacent to the apiaries.
Any thoughts to why this might be so?
The final direction taken obviously depends on what the scouts have
determined as a suitable home.

Peter
P.S. Answer to the inevitable question - why were the swarms left to fly
off?
- I do not climb up oak/ pine or any other tree higher than 4 meters!
Vertigo!!!!