Sorting thrushes

I don't aspire to learn the identity of every bird species in the world, but I would really like to be able to identify all the species that visit the oasis. Recently, that has become a problem regarding thrushes (haven't sorted out the empidonax flycatchers either), and Byran Tarbox's discovery of a Gray-cheeked Thrush a few days ago only compounded my confusion.

In trying to sort this out, my research indicates there are at least seven subspecies (or geographic races) of Hermit Thrushes. My problem is, how will I know if I'm seeing a subspecies of Hermit or a Gray-cheeked, or even a Swainson's? (Apparently I couldn't have a Bicknell's because they're only in the northeast US.)

A month ago I had a thrush I couldn't ID (pictured here).

Kelly Bryan told me it was the larger subspecies (auduboni) of Hermit Thrush that has paler rufous and larger spots, and migrates through in May. Well, now I can't differentiate it from Bryan Tarbox's Gray-cheeked, although I haven't actually seen the latter in person (photo on previous post). Maybe if I saw it in person that would help. If it sticks around I should be able to see it.

UPDATE: Well, I solved the thrush sorting problem. From now on I'll take photos and let the experts sort it out. When I couldn't restrain myself any longer I loaded up my partially dried apricots and headed to the oasis. In the 2 hours I sat watching for the thrush I saw its head pop into view and then it flew. No photos, no good looks. Maybe in the morning. Anyway, after dark I went to my birding library and found a 3-part, in-depth study on the spotted thrushes (Birding Magazine Apr, Jun, Aug 2000). There are even 2 subspecies of Gray-cheeked (minimus and aliciae), so I know I'm out of my element. All I can say is that in the brief look I got at the Gray-cheeked it did look very unlike a Hermit Thrush.