The bright light will make the animal feel insecure because potential predators can see and cause it harm. It also makes it hard for the animal to sleep, so the animal will search for a darker and safer location. Invade the Attic with Loud Human Voices. Place a radio in the attic tuned to a talk radio station. Raise the volume so that the sounds reach the entire attic.
Humans are deadly predators and strike fear in animals.
Wild animals do not want to be around people and by providing constant human voices, you make the attic a scary place. Don't play music, only talk stations will scare the animals. You have eliminated every reason the wild animal chose your attic. It is now a smelly, bright, and nosey place. The animal must now find a new home.