I've been lucky to study a large number of Hoary Redpolls in the last year, and have written an article on my experiences with the subspecies. It is designed to introduce someone to Hornemann's, if unaware before. Direct link here:
I encountered a large feeding flock of Redpolls on Feb 18, 2011 in northern Ontario, which contained at least 4 Hornemann's, which provide many of the images for the above link. This winter has produced several "Hornemann's" in Ontario, and they could still be moving south. This subspecies has records in Ontario well into April, lingering longer than expected - so the next month could be a great time to try and find these snow-monsters!