This is a quote from Twin Peaks, a surreal television series that originally aired in 1990 and 1991. Very little in that series was what it seemed, so pointing out the owls was somewhat superfluous. The owls, like the traffic lights, were a recurring theme of debatable significance.
Owls in particular aren't very significant in the everyday lives of most people, but the sentiment is. Don't take so much for granted. There will always be something that's not quite what it seems.