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Message: <blockquote data-quote="chris butterworth" data-source="post: 2099715" data-attributes="member: 64315">Just reading through David Sibley's article and I picked up on " The two subspecies interbreed freely where their ranges overlap, but their ranges barely overlap, so intergrades are rare.  Intergrades are probably about as frequent as pure males in North America, or maybe a little more frequent.........." ( my highlights ).  I have to admit it seems a little like blasphemy picking up on this, considering the amount of work DS puts out but, does he mean pure males of Green-winged or Common are less frequent than intergrades and, if there is limited hybridisation in the small areas of overlap then don't we have a similar case to Carrion / Hooded Crows?ChrisAnother thought just occured to me.  Are North Americans entering a 'lumping' phase ahead of the rest of the world.  I hope not!C</blockquote>