I'd say their theory is bird-brained but birds are smarter than that.

From a Scientific American article:

Darwin concluded that color differences between sexes in birds... result largely from female preference for bright colors in males. This general rule has received much support since Darwin's time, but other influences have also been noted. For example, females of species that are exposed to predators while incubating tend to have dull colors.

Sometimes I'm fascinated with how evolutionists' minds work. Secular scientists claim they go wherever the evidence leads. In practice, though, they only go where evolution can lead them. As we study birds, for example, they don't ask, “Why are some birds brightly plumed?” Instead they ask, “Why did bright plumage evolve?” Evolution is the paradigm through which they interpret the evidence. Therefore, their conclusions will always seem to support evolution. It's a vicious, circular argument.

Let's consider the quote from Scientific American. Their point is that bright feathers in male birds evolved because female birds are attracted to the bright feathers (known as sexual selection). At the same time, female birds have drab plumage because, during nesting, bright feathers would make them more visible to predators. In both cases, there seems to be an obvious survival benefit in having bright or drab feathers. The evidence, therefore, could be said to support evolution. This is a standard argument which I've heard made many times before. Such simple attempts to describe the origin of bright plumage sound plausible at first. However, I don't believe they can stand up to scrutiny. I see in them a host of unanswered questions.

First, explanations like this still don't answer why bright feathers evolved. I know what they're trying to say: that the male birds with the brightest feathers are the most successful in attracting mates so the brightest plumage is selected more often over the drab. But evolution is not a directed process. The desire for bright plumage does not cause bright plumage. That would be sort of like saying that dinosaurs evolved into birds because they wanted to fly. For females to select bright feathers in a mate, bright feathers must already be present in the population. If there is not bright plumage, sexual selection will not create them no matter how hot the hens think colorful feathers are!

This tactic of using the survival benefit of a feature as the explanation of why the feature evolved is prevalent in evolutionary philosophy. I wrote about this a while back after reading an evo-article that said crying evolved as a way for humans to garner sympathy from each other. No it didn't. Still, I hear stories like this all the time: lions evolved heavy manes to protect themselves while fighting. Giraffes evolved long necks so that they could reach the leaves at the tops of trees. Poisonous frogs evolved bright colors to warn away predators. The list goes on and on. It's about as ridiculous as believing that Michael Jordan grew tall in order to play basketball. Merely pointing out the survival benefit of a trait is not a sufficient explanation of how or why the trait evolved.

Another funny thing about these types of explanations is that they are so flexible that they can describe anything. Male birds evolved bright feathers to make themselves more attractive to females while females of the same species evolved drab feathers in order to make them less noticeable to predators. Wow! Members of the same species evolved completely opposite traits in exactly the same environments for completely different reasons.

I've also heard that humans evolved altruism because there is a survival benefit in a peaceful, cooperative community. Except, of course, when we express aggressive behaviors like fighting, raping, and killing each other. In that case, years of field research has taught us that we're acting the same way as our cousins, the chimpanzees. One story... er, I mean, “study,” says that we're monogamous because that insures the greatest chance of rearing our progeny to maturity; but another story says we're habitually unfaithful because our evolutionary success hinges upon leaving the greatest number of offspring.

I'm reminded too how often we hear that similar structures in different species are the result of shared ancestry – except when they're the result of convergent evolution. How predictive can any scientific theory be if it can be used to explain anything – even completely opposite results in the evolution of members of the same species?

Yet perhaps the funniest thing about the Scientific American's explanation is the seeming circular nature of it. Think about it: make birds evolved bright feathers because female birds are attracted to bright feathers. It's a tautology. The next question should be obvious: why are female birds attracted to bright feathers? If evolution were true, the preference for bright feathers is also an evolved trait. The evolution of bright feathers isn't necessary unless a preference for bright feathers had already evolved. Yet how could a preference for bright feathers evolve before there were bright feathers? What a pickle! And by the way, what survival benefit is there to the species for the female of a species to be attracted to the males who are the most visible to predators? That part of the equation isn't as neatly explained.

It's sad, really, that scientists waste their time inventing these “just so” stories that have no value as scientific theories and, frankly, don't even explain anything. They then foist these half-baked ideas upon the unsuspecting public and have the nerve to be appalled that lay people just don't understand evolution. Is this the kind of evolution Bill Nye believes kids need to learn in order to be good scientists?

“Good morning, class. Today we're going to talk about bird evolution. Please turn off your critical thinking skills and don't ask any questions.”