There are some things that seem odd about this author's terminology.<p>> ...the evolutionary mechanism behind this novelty is not adaptation by natural selection, in which only those who survive pass on their genes, allowing the species to become better adapted to its environment over time. Rather, it is sexual selection by mate choice...<p>In natural selection, it is only individuals which <i>mate</i> which pass on their genes -- surviving is no good if you don't mate! It is my understanding that sexual selection has been classed as a variety of natural selection. If the species sexually selects itself to a point of maladaption, it goes extinct -- just as if it was maladapted to its environment for any other reason. Notably, these birds are not there: they still seem to be okay.<p>> In the absence of direct costs to the choosers, the population will not be saved by natural selection. Because the cost is deferred, the whole population can ease further and further into maladaptive dysfunction, generation by generation.<p>This seems to be treating natural selection as a game of one round, or describing a situation where there is almost no capacity for variation in the species. But if it's really true, that the species is in a kind of dead-end, where the most successful mates are the most maladapted, and there is little capacity in the genome to remedy this situation -- as the females could develop a different standard of attraction, or the males some other method of attraction -- then the effect of natural selection would be to extinguish the species. This is, in some sense, how "progress" is made in natural selection -- as much by elimination as anything else. This leads us to:<p>> Instead of ensuring that organisms are on an inexorable path to self-improvement, mate choice can drive a species into what I call maladaptive decadence...<p>It has been said by many more well informed than I am, that there is something specious about an "inexorable path to self-improvement" with regards to animals. Animals become more adapted to their environment; but they don't become "better animals" since a change in the environment leads them to be worse adapted. The subtlety is that, traits may be gained, and then lost, and both were "better": to gain fur as the earth cooled, and to lose it again as the earth warmed.<p>And finally I must ask, where has the author shown the birds are maladapted? They fly awkwardly, sure -- but what difference does it make for them?