Well this is where it starts to get weird and extra nerdy on my part. BUT here it goes, that birds typical range is from the central planes to the west coast. TYPICALLY they are within that range during the winter months, they migrate to the states with the cold weather. They like cold, but not winter time in canada cold. So what probably happened is that it got mixed in with a flock of birds that typically comes to the midwest during winter, plus add in the weird weather patterns we have been having with the jetstream, it got lost. This sighting today marks it as the 6th time in St. Louis one has been found. So thats cool.
That's really cool. Hopefully you get a chance to see one or two more this season then.
My brother has been using the T3i we got him for xmas a little bit. Got to get him set up with LR and Flickr so I can share his stuff. He's big into ornithology after a few courses he took last semester and over the summer at college.