Yesterday I used the Merlin Phone App to identify unfamiliar bird songs. I thought they came from a mockingbird, but it turned out it was a brown thrasher, and that ID seems to have been confirmed by the appearance of these thrashers near my suet feeder. Hear its lovely song here: https://youtu.be/nE4IeNZy760?si=pYJDT4O2CJcl-0y0

No wonder I thought the song I heard yesterday was from a mockingbird, according to this post on allaboutbirds.org: "To find Brown Thrashers, keep your eyes and ears alert around tangled thickets, hedgerows or forest edges in central and eastern North America. Brown Thrashers are secretive, and hard to spot in their favorite spots under dense vegetation, but they can make a lot of noise as they rummage through the leaf litter. During spring and early summer, males climb higher to sing from exposed perches. Listen for a song with a pattern of a Northern Mockingbird, but with phrases repeated only in pairs rather than in triplets."