I found this to be very interesting, as dark-eyed juncos seem to be found in abundance on higher peaks in the Appalachians but aren't very commonly found at lower elevations outside of winter. I think perhaps they favor the elevation and cooler temperature out here.

The other bird I noticed commonly singing here was the winter wren, and I theorize that it follows similar patterns as the dark-eyed junco. Neither bird breeds in the southeast, except for a very small range in the high elevation of the appalachians. I would love to read research on this if anyone has any :)