That is why visible mutations are rare in the wild in general. Most mutated animals that are prey animals never have the chance to breed and produce enough offspring to give the recessive genes a chance to express themselves. They stick out like a sore thumb and get eaten, killed, or just plain ostracized. In some groups, especially some bird groups like finches and parakeets, recessive mutations appear quickly in colonies that stay together. Any expressed recessive mutation in nature is proof of the inbreeding that really occurs.That may be the case,,but I ask you,,if barred winged birds was first,,,,where or how did B/S come about with quite possibly one bird having that gene and breeding to very possibly another bird that did not have b/s in their genetic toolbox?