According to Allaboutbirds, the Brown Thrasher has one of the largest repertoires of any North American songbird, up to 1,100 song types. Ours was playing its greatest hits but kept coming back to its version of the whip-poor-will, a nocturnal bird that has kept us awake during its breeding season. The other key to identifying the call was its repeating the song twice, then immediately starting the next tune while a mockingbird tends to repeat it three times.
The Brown Thrasher is rather distinctive with its long, slightly curved beak, long tail and a bright yellow eye that is prominent. They migrate up this time of year, extending all the way to Canada. There are reports of individual birds reaching Germany and England once each, probably on a foreign vacation. Lisa Berger came up with more range data: "
"They are listed as an uncommon Southern Missouri winter resident. Locally, we see them on Christmas Bird Counts, similar to E. Phoebe. These guys are more common in winter than my perception simply because they aren’t singing!"

They feed on the ground as well as gleaning fruit and berries
in season. Currently they are working our lawn, sweeping it with their
long beaks looking for any available insects. Then they fly up into the trees or wires to announce their presence, call for a mate, or just sing because
it is a beautiful morning. I went out to listen again this morning and was rewarded with a bird singing on the wire. While our great sonic "discovery" didn't advance ornithological science, it made our day a little brighter.