Sounds like a Yellowthroat in the middle. I agree it's a House Finch.
Purple Finches are well know mimics and a close relative.
On Fri, Mar 22, 2019, 12:29 PM John Powell <jsp255@xxxxxxxxx> wrote:
This morning at Mt. Tabor Park I heard an apparent House Finch singing a
very strange song that seemed to contain mimicry. The very beginning (and
sometimes the end, as in this recording) sounded normal, but the middle
contained a descending three note phrase repeated three or four times. I
only saw the bird as it was flying away (with another presumed House
Finch). I didn’t see it well enough to ID it visually, but nothing I saw
ruled out House Finch.
Recording here:
https://macaulaylibrary.org/asset/146698951?__hstc=60209138.b0cb43c2aba5afb3847ddea4fc7c3cf3.1531508988503.1553111346353.1553282145473.112&__hssc=60209138.3.1553282145473&__hsfp=2413317908
John Powell
Portland
