The birdscare humming line, is a scarecrow in a tape. It is a tried and tested organic bird deterrent. 30 metres (100ft reel) of the polypropylene tape is supplied. The tape emits a penetrating vibration that birds won't go near, just stretch between two stakes and it will start to vibrate.The sound and movement will vary, so birds do not get use to it. The humming line will also deter rabbits and other pests. Ideal for protecting vegetables, fruit and newly sown lawns.
Also works great on boats, to rid seagulls mess!
We'd better get some of that! Simple, cheap & effective. Jane Moore, Organic Allotments, Gardeners World Magazine August 2007
What birds hate even more than the noise of the bird humming line is to be surrounded by the line on all sides (see diagram) The birds see the lines as a spider web, endangering their landing and take off. So using all the 30 metres of humming line, create lines in all directions, criss-crossing your plot.