What is Reddit's opinion of Aspectek Stainless Steel Pre-Assembled Bird Spikes 10 Feet (3 Meters), Bird Deterrent Kit with Transparent Silicone Glue?
From 3.5 billion Reddit comments

By popularity on Reddit, this product is:

#470 in Lawn & Garden Low Return Rate Alert

As an alternative, I've had zero problems after I added these spikes

It makes your balcony less attractive to them so they just go to one of the other ones and you don't need to cover your space in netting.

I use these to keep my cat off of my Lizard's vivarium, just attach with zip ties or even Velcro:

< $50

< $50

$50 - $100