If your criterion of speciation were inabiility ever to produce fertile hybrids, there would be perhaps 4 species of duck on this continent.
Well, this is probably where we have a divergence of view points. My background is in Botany so I'd use the example of Oak Trees, and while the botanical nomenclature may make Pin Oak and Red Oak distinct species, the fact that they can produce fertile offspring makes them the same species, but different varieties in my mind.
Before they were domesticated, they were segregated by habitat, and I suppose you could say this was enough to make them separate species, that's just not how I (and most advocates of inteligent design) define it.
Owl_Eagle
(If what I just wrote makes you sad or angry,
Problem is, no birder or hunter has any problem with the idea that Mallards and Pintails are separate species. Pintails all pretty much look the same (well, the male drakes in normal plumage do) and mallards all look the same, and mallards and pintails look very different. Any decent birder can tell them both from shoveler, and redheads, and canvasbacks, etc.. And we knew them as species long before evolution ever came along. 'Species' is a perfectly reasonable category for all of them. Yet under exceptional circumstances they all interbreed.
Group A can successfully interbreed and produce fertile offspring with group B. Group B can produce fertile offspring with Group C. Group A, however, cannot interbreed with Group C.
How would classify Groups A, B and C?
Simply an ongoing speciation process and you're a lumper rather than a splitter.