We are accustomed to arguments from Creationists, and some of those arguments are in my opinion really valid, like the Cambrian Explosion argument. However Evolutionists are some times deluded by them self, and that is a shame.
Ring Species are the greatest evolutionist delusion, first because you can't prove ring species at a macroscopic level, and secondly, the only valid study on a supposed ring species proved otherwise.
At a macroscopic level a Chihuahua isn't able to interbreed with a Pit Bull, despite belonging to the same specie! However, if you doubt the need of the artificial insemination of the previous example, think in the French Bulldog, that is unable to naturally interbreed with the same kind dogs! What about that?
Ring Species? I don't think so!
So, you can't say you have a Ring Species just because macroscopically two supposed ring ends' organisms don't interbreed! However, it's very strange how evolutionists accept as scientific fact this evident delusion.
A truly evolutionist would say, wait! Wait, the only scientific study at microscopically level proved that the classic example of the Larus gulls aren't a ring species... Wait, stop the fairytale!
Thankfully scientists don't speak at a single voice, and being so, Liebers et al. made the evident conclusion, the herring gull complex is not a ring species.
So please, don't be far-fetched, be simple like Darwin have been.
Illustrated Ring Species illusionist trick by Escher
Ring Species delusion - Part 1
Ring Species delusion - Part 2
Ring Species delusion - Part 3