The track shares some similarities with the early track "Rodox Video". Some even believe that "Rodox Video" is in fact an early version of "Peacock Tail".
The human voices that start around the 3:07 mark are a distorted sample of the Azan/Adhan or the Islamic call to prayer, probably this one in particular.
One of the voice samples could also be from The Elegants - Little Star. Here is an audio clip to demonstrate this theory where both tracks are overlayed and slowed down:
Apart from being the most colourful feature of the peacock, it was also a figure used by Euclid to prove the Pythagorean theorem.[1]
The NBC Peacock, one of the most famous TV station logo in the USA, features the colours of the rainbow. Rainbows are frequently referenced in Boards of Canada's music (see: "Roygbiv" on MHTRTC)