Robins are the most difficult to deter. Flash tape, whirly gigs, scarecrows don't work on them. The only think that has helped me is netting. I also go out and shoot at them with my pellet gun, but I'm a terrible shot. The few I've hit are genuinely shocked, but never really hurt. I still have to say it sure makes me feel better.

Bird netting

ROW COVER, birds get tangled in netting.

I was afraid netting was going to be the answer. Not sure there is a realistic way to net these trees due to their height. Gred, we have had the same experience shooting at them. I'm pretty sure the few airsoft pellets that actually made contact only served to increase their determination!

Birds may get tangled in netting, and some of the cheapest kinds may be damaged by them. On the other hand if it holds them there's nothing better to deter more than one flapping around trying to get out. Sounds cruel when I say it out loud, but it certainly works.