It turns out that butterflies with eyelike spots evolved to scare off predators. A recent study concluded that about 68% of the birds that were shown an image with eye-mimicking spots, flew away or showed signs of being startled such as chirping a warning call as they flew in for food (within a controlled setting). That’s on par with the 57% showing the same reactions to the owl with open eyes, the research team notes. The full study can be analyzed in the link below:
Source: http://rspb.royalsocietypublishing.org/content/282/1806/20150202