Okay so I didn't see it posted yet but the best deterrent to birds crashing into your windows at every level is cut out owl pictures. If you want to be fancy and have the room, these statues would be excellent outdoors
Hausse 2 Pack Fake Horned Owl Bird Scarecrow Decoy, Plastic Owl Bird Deterrents, Halloween Outdoor Decoration, Nature Enemy Pest Repellent for Outdoor Garden Yard https://www.amazon.com/dp/B087X7XXJL/ref=cm_sw_r_apan_glt_i_TTRSG40FA0DGQKQV1GS5
But don't do like my elderly friend did, and crochet something colorful and owl shaped. That doesn't work.
In office buildings and houses just print out a full page sized owl in graphic detail and tape it up facing out. Animals not harming themselves and your property is more important than what your neighbor thinks about the fierce faced owl in your window
(OvO)
These fake owls are amazing for keeping crows away.