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Message: <blockquote data-quote="Mysticete" data-source="post: 1603218" data-attributes="member: 67784">I suspect this argument will go in circles until the sun supernovas, but...I think that perhaps you grossly oversimply changes in taxonomy viewpoints within the last two centuries, nor do I believe they are completely driven by conservation in the vast majority of cases.For one, the 19th century approach to taxonomy was rejected largely because it was way too typological, and failed to understand that individual variation was a major issue to consider in many cases.  Add in the artifacts of the time (slow speed of communication, researchers having to do with dead and perhaps poorly preserved specimens, and lack of time to assess collections), and taxonomists tended to ascribe every new variation as a new species, hence twenty or so species of cassowaries for instance.Early last century researchers tried to approach taxonomy in a more rigorous fashion and thus the biological species concept was formed.  However in many cases this concept was misapplied, leading to lumping of just about anything that could hybridize, even if only rarely or only in captivity.  In addition you had a lot of sweeping revisions of taxonomy, with little peer review in many cases, which led to mass lumping of species/ genera/etc with little and sometimes no actual evidence for the change.  In fact, this is often times listed as a reason for "going back" to earlier ideas, at least in SAC and AOU checklist proposals.Nowadays it's not that we have reverted to a 19th century taxonomic approach, but we simply have tools that earlier researchers couldn't have dreamed of.  We can use molecules to test polyphyly and paraphyly of species, assess phylogeographic patterns, divergence dates, and hybridization.  We have access to large collections of material to assess variation in morphology, not to mention morphometric approaches to quantify it.  Researchers undergo complicated field experiments and study sonograms to assess reproductive barriers.  In other words I believe the change in taxonomy is being driven by actual science, not just a shift in attitudes.I no longer am a adherent to strict PSC bird classification, however if you look carefully you see that pure PSC splits are seldom well received by checklist committees or most major taxonomic bodies.  Certainly the PSC splits in Tiger, Wolf, American Marten, etc have not been accepted by anyone, nor do I think it is likely unless more research is done to verify them.  If you look at the most recent AOU checklist proposal (sorry if I have to keep falling back on the New World, but it's what I know best), all three splits are BSC splits.  Pacific Wren and South Hills Crossbill both assortatively mate and do not recognize other forms as being conspecific.  Even the dodgiest BSC split, the Scrub Jays, utilize different habitats and have a very narrow and small hybrid zone.I personally don't feel as enough research has been done on old world crossbills, or even New World forms, to feel we are ready to split them quite yet.  However if the different forms, or at least a few forms, do assortatively mate and inhabit different ecological niches, than they are good species under any definition we use.</blockquote>

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