Pigeon scarers

This is a bit of a random thought really…
I haven’t been to the space properly yet as I haven’t any good ideas for things to make.
I was thinking I could make something to scare pigeons from my balcony. I have tried plastic owls and windmills etc but nothing seems to work. So I though something automatic (like a bird shaped silhouette with flapping wings which is triggered by a sensor or a spinning reflective object or…)
Ive made various sensor triggered art objects in the past so I have the basic electonics.

So if anyone has had any pigeon experience and knows what might work, I would be interested to hear. Most things for deterring pigeons work for a bit but become useless once they get used to them.