Sunday at the Bus Station

On Sundays, high days and holidays, when the sap is rising or the sun is high in the sky, the bikers flock into Abergavenny. They are attracted to the bus station (there being precious few buses on those days) like bees to the hive, or ants to spilled sugar, or vultures to a dead zebra, or kids to a sweet shop...
There they drink tea from the bus station cafe and admire each others' mounts. Then groups drive off to some other resting place to repeat the process, probably somewhere in the Brecon Beacons.
This behaviour has been observed, but where they come from and the reason for the migrations is still a mystery. Unlike eels and salmon, it appears to have nothing to do with mating.