Well, in addition to the MacGillivray's Warbler that has been reported in the Chicago area, there has also been a report of a flock of (possible) Long-Billed Curlews, and of a Kirtland's Warbler. Up to this point, only the Kirtland's (seen at Gilson Park in Wilmette) has been photographically documented. (Anyone want to guess where the loyal BINAC staff will be tomorrow?)
So, are all of these birds legit, or not? The person who originally reported the "curlews" was not really even sure that they were LBCs (as opposed to Whimbrels) so that sighting is probably not going to be accepted by IORC, if it is even documented by the observers at all.
The Mac-G is a bit of a tougher question. It was seen by a few people on the "second day," but already I have heard some grumblings that a Mac-G cannot be safely identified in the field. I suspect that the IORC (Illinois Ornithological Records Committee) will have some healthy skepticism about this bird. There is one prior (very old) specimen record, so I think that the IORC may treat this as a first-state record, and will want to see a photo or sound recording.
The problem is that some Mourning Warblers (even adult males) can have at least faint eye-ring "arcs." I've been saying this for years, and people tell me I'm crazy, but it's Dunn and Garrett. D&G also states that some adult Mourning Warblers can have what appear to be black lores. So, even though the description of this bird strongly suggests Mac-G Warbler, I'm not sure you can totally exclude Mourning Warbler.
Hmmm, we'll see.