Animals use a variety of ways to camouflage themselves, i.e., to make themselves less detectable to visual predators (such as birds). Sometimes they're cryptic and match the color of their background. Other times they have disruptive coloration — conspicuous markings that break up the outline of the body. This makes it more difficult for a predator to recognize the prey.
The moth in the photo above demonstrates both cryptic (matching the wood) and disruptive coloration (strong black lines that are distracting and make it hard to see the true outline of the moth). [I'm not sure about the identity of this moth, but I am wondering whether it's a species of Digrammia?]
Below is another example. The color pattern on this Painted Tiger Moth (Arachnis picta) matches the lichen-covered fence, and the stripes make it more difficult to identify where the moth ends and the fence begins. From a distance, it's hard to tell that this moth is a moth!
Although easy to overlook because they effectively make animals disappear, keep your eyes open for other examples of cryptic and disruptive color patterns!