This is Gustavstraße, the oldest part of Fürth, where the buildings are all different heights. Fortunately this project, to hang up one thousand plastic ‘ravens’ to frighten the pigeons away, is apparently only going to be around for three weeks, I was relieved to hear.
Fürther Nachrichten story Raben gegen Tauben (German)
There have been peregrine falcons in Fürth, but I don’t know if they’re there this year. Another possibility is dummy egg nesting, but that would have to be done by the city.
LATER NOTE: I picked up two of these for a friend. They are very well made, with a sort of post diagonally through them, so they can be suspended from a hook at various heights or stand on their feet. I later discovered the same ravens, including the flying ones, are available cheaper from amazon.de, albeit not painted yellow. I suppose it is a work of art if you make over three euros on each one (less postage) just for putting your signature on it. I know artists’ signatures are worth a lot.