20 000 -10 000 yrs: By now, the humans form many bands/tribes, except that in the bird-dominated areas, human tribes are loosely associated with a group of birds similarly from that region. Each develops, mutually a different language and customs.
At this stage, humanity has architecture consisting mostly of huts into small villages of thousands of people, materials mostly pottery, ceramics, wood, stone, fur clothing etc. It is mainly our species, with our workable hands that develop this initially, but the birds also start to learn and gain from this. Specialization starts to occur, as they did in OTL. Some people start to be chiefs, craftsmen, warriors (to fight neighbouring tribes), hunters, (rice) farmers while the birds, relatively limited in manual flexibility, nonetheless help with the sowing of seeds, gathering of fruits etc. The birds, with their excellent hearing, sight and memory, can act as scouts, the eyes and ears of the tribe. The birds are also extremely artistic and paint/decorate the villages and charm humans with song and dence. The birds act also as shamans in religious ceremony. Trade arises among the people and birds as well as with neighbouring tribes.
-Humans move into the Americas via Bering strait (around this time if I recall correctly)