Name: greene Savannah, GA (Sunset 28) (Zone 8b) I have no use for internet bullies!
The Solanum was most likely not in the birdseed but rather was a gift from the birds who had been feeding on the Solanum seeds elsewhere and deposited the seeds in your yard when they stopped to feed. After the first year the plant will show up nearby or wherever else the birds carry the seed.
Sunset Zone 28, AHS Heat Zone 9, USDA zone 8b~"Leaf of Faith"