River Earn Walk, Crieff, Perthshire 25/7/10

Apparently honey bees wings stroke at about 200 a second(!) and this is what causes the buzzing noise.  Recently when walking down through a wooded walk (Laggan Hill, Crieff, Perthshire) in the late evening I heard 2 lots of many bees. I go that walk a lot in the morning and never hear the bees, so I presume they are out working in the daytime?  I was told that they can be found by Sycamore trees and sure enough there was a Sycamore tree right beside the noise both times.