The excerpt above is an excellent introduction to many of the popular mysteries of the Ancient Druids knowledge:
Meaning, A Reading
“HE who knows the ways of beasts and birds”
As observers of natural phenomena, they knew the tendencies and characteristics of birds and animals but also held the knowledge of their sacred and spiritual importance.
The “bright quicksilver life” refers to an understanding of physics and motion.
The course of the stars refers of course to astronomy and astrology, both the method of tracking the stars and the significance or influence of the positions on humans.
Timeless knowledge and experience is the realm of the mystery.
The druids were moral philosophers. Similar to the druids in their training and knowledge were the bards (bardoi) – singers and poets, and diviners (vates), who interpreted sacrifices in order to foretell the future.
The final lines talk about the worship, comfort and reverence for nature. Nature as a temple.