Fake owl probably wouldn't work.
Bobcat Urine might.
It's available on Amazon: https://www.amazon.com/Predator-Pee-Bobcat-Squeeze-Bottle/dp/B016MY3ZPY
Spray some of this around the house or HVAC. Or freeze it.
https://www.amazon.com/Predator-Pee-100-Bobcat-Urine/dp/B016MY3ZPY
You can find coyote and Bobcat urine on Amazon. https://www.amazon.com/dp/B016MY3ZPY/ref=cm_sw_r_cp_apa_glt_fabc_285V2ZSY089D4CYCZJV7 Sprinkle it around your garden that wii scare them away.