In the Munkdaka Upanishad, Shloka 3.1, it refers to two birds on a tree – one is ParamAtma and the other the JivAtma: Dva suparna sayuja sakhaya samanam vriksham parishasvajate | Tayoranyah pippalam svadvat-anashnan-anyo abhicakashiti || Meaning: Two birds, one representing the Par...