One complication: Hermit Thrush was one of the several species noted in the "DNA Barcode" study 12+ years ago where two samples from different regions differed as much as was typical of related separate species. To my knowledge the needed follow-up has not been done, but it would not surprise me if "Hermit" Thrushes from different parts of their range have some different calls. In any case, the differences in size and plumage among the various forms appear greater to me than intraspecific variation in other Catharus thrushes.
IMO comparisons to Xeno-canto recordings of "Hermit" Thrush calls need to be interpreted in the context of which Hermit Thrushes might be involved.
From: "rriparia" <rriparia...> To: "Tom & Allison Mickel" <tamickel...>, <lanebirds...>, "obol" <obol...> Sent: Sunday, October 20, 2019 1:22:09 PM Subject: [obol] Re: Question about Catharus thrush call
I checked Hermit Thrush and found quite similar calls on Xeno-canto:
XC21120, Recorded by Paul Marvin, 11/10/2014, page 3
XC65824, Recorded by Ian Cruishank, 11/08/2010, PG 4
I recorded a Catharus thrush this morning on my morning walk on the ridgeline trail in SE Eugene. I've heard the bird calling in the same location four mornings in the last week. In addition to the call I recorded, I've also heard a very high-pitched thin note from a thrush in the same location. After listening to calls of Catharus thrush on Cornell's website, it sounds most like a Gray-cheeked Thrush, but I'm wondering what other people think. The recorded call sounds most like the second recording on Cornell's website, and the high-pitched thin note sounded most like the fourth recording. The recording was made at 7:20am, and I saw the thrush hopping up the trail in front of me, but could not see any details because it was too dark.