chiffchaffs and Spaniards

Biologists are currently going through a phase of species 'splitting'. That is to say that what were once considered variable, widespread species are now being split into two or more species. Little green warblers in Europe, lots of marmosets and monkeys in South America and numerous other species all over the world are suddenly being created. But some of the differences are so small that I wonder if these splits are justified. If an Iberian Chiffchaff has a slight difference in song, and some very minor plumage differences to those found in England does it really make it a different species? After all Spaniards sound different to Englishmen, sing different songs, and on average look darker. But they are certainly not a different species. They can (and often do) interbreed with English women. And so, I suspect, could the Iberian Chiffchaffs, interbreed with English ones, given a chance. Just like their human counterparts, language differences may make it difficult, but not impossible

In terms of taxonomy, it makes relatively little difference whether or not they are considered geographical races (subspecies) or allopatric species. It does however, have a conservation benefit, in as much as it can highlight declines more accurately, and it probably has increased the number of endangered species being identified. But is this a good thing? Or is it misleading? Answers please......