I've had one, seen out of my kitchen window. It was perched on a tree behind a house across the road, the exact tree that one was in 3 years ago!
The fuzziness of all supposedly absolute taxonomic distinctions - Stephen Jay Gould (1977) "Ever Since Darwin: Reflections in Natural History".
Species and subspecies are but a convenient fiction - Kees van Deemter (2010), "In praise of vagueness". Biology is messy