Collar and Spottiswoode clearly missed the point. I did not “propose a whole new set of methods,” advocate a particular species concept, or recommend any technique as definitive. Rather, I evaluated current practice in bird taxonomy to learn how species-limit decisions are made in ornithology.
My central tenet is that birds are treated differently than other vertebrates; birds are described and diagnosed primarily using traits we can see and hear under field conditions. This is not an unqualified opinion nor a position statement, but an objective conclusion based on quantitative analyses of species descriptions during the last decade. Using detailed case studies, I demonstrate that field marks do not necessarily represent overall variation—some birds vary in ways we cannot detect in the field. Instead of dismissing this issue or ignoring the associated implications, I proposed several solutions. Using morphology, anatomy, molecular differences, or any other objective attributes, we can complement these visible characteristics and improve our understanding of how many species we are really dealing with. And yes, this will result in more species under any species concept. This is neither good nor bad; it's merely a better representation of actual diversity.