Plastic owls temporarily frighten away certain animals, including those that might be making a nuisance of themselves such as pigeons, seagulls and rabbits. The effect is not usually long-lasting; these animals are intelligent and quickly realize that a plastic owl statue is not really a threat. It could, however, give you time to take other measures, such as installing a fence. You might simply find plastic owls appealing as a decoration. Attaching one doesn't take long if you have a ladder and are physically fit.
View your roof from the ground if you want to scare rabbits. Sit or crouch to get a rabbit's eye view of the roof and note clearly visible spots. With birds, the location is not so important provided the owl is high up.
Unwrap the owl. Pull out any packaging material and discard it.
Fill the owl with sand, grit or gravel to add stability. A hollow plastic owl is easily blown away.
Set up your ladder in the appropriate location. It is safest to have somebody else hold the base.
Use the mounting equipment that comes with the owl as per the instructions. Alternatively, drill holes through its feet prior to ascending the ladder and screw or nail it in place.