Complex sentence: This species is difficult to separate from Parrot Crossbill and Scottish Crossbill, both of which breed within its Eurasian range, as plumage distinctions from those two species are negligible, though the head and bill are smaller than in either of the other species.
Split into simpler sentences: This species is difficult to separate from Parrot Crossbill and Scottish Crossbill, both of which breed within its Eurasian range. The head and bill are smaller than in either of the other species.