You may already know about this, but I was not aware that a pure white Blackbird (the thrush, not the icterid) can be found at Rufford Abbey Country Park in Nottinghamshire, UK. In fact, this leucistic lovely (check out the pic) has resided at the park for the last four years. Thanks to reader Sher Buckner for the tip.
BONUS TRIVIA: Nottingham is , of course, also the home of famous archer, outlaw, and liberal economist (I kid!) Robin Hood.
Mike is a leading authority in the field of standardized test preparation, but he's also a traveler who fully expects to see every bird in the world. Besides founding 10,000 Birds in 2003, Mike has also created a number of other entertaining but now extirpated nature blog resources, particularly the Nature Blog Network and I and the Bird.
They called this bird a “leucistic” but some people may disagree and call it an “albino” instead. And this is exactly what Hein van Grouw did in this article about this subject:
van Grouw, H. 2006. Not every white bird is an albino: sense and nonsense about colour aberrations in birds. Dutch Birding 28: 79-89.
PDF here: http://www.vogelringschier.nl/DB28%282%2979-89_2006.pdf
There is an albino Eurasian Blackbird in page 3 very similar to the one reported here.
Regards from Morocco