Bird control spikes on the roof

Around our house, many birds are living, but mainly pigeons choose our roof as a landing place. The ridge is their favourite spot and they prefer the very ends of it. Frequent visits result often in excretables on the light in the front of the house and the terrace in the back. Given the size of these excretables, it is far from pleasant to do the cleaning afterwards.
Other birds landing more recently on the chimney are crows. They travel between our neighbours roof and our chimney and because of their destructive behaviour they are not wanted here. They attack the plastic parts of the double-walled chimney and make a lot of noise.
The initiative was taken to make bird control spikes from some plexi (PMMA) lying around from the construction of my hobby room and some steel wire from our neighbour. The construction proces is documented in the next series of photos.





The plexi glass is very handy to work with and the elements are glued on the roof with silicone glue from the Aldi supermarket.
The pictures from the 65 year old acrobat on the roof fixing the spikes will not be shown so far.