Thanks for reporting on this bird Lucian. To add to the location – there are three large sets of powerlines that run North/South. The bird was skulking around on the south side of the river under the most upstream (eastern) set of powerlines. As mentioned, lots of berries, and a group of several larger trees. There were 2 Hermit Thrush following each other around in the same shrubs.

The mockingbird was still present at around 10:30 AM. Right where you tagged on the map, on the South side of the river with some red berries.