The brain is a physical perception center designed to inform by capturing boundaries and identifying patterns within them. The absence of vibrations within the human perceptible auditory range is generally defined as silence. Per this, silence is but a gap, an auditorily imperceivable gap.
The author, I think, speaks of a different silence. The kind that's not heard, it's not even felt. For its not what the brain can know, it's that which engulfs. The kind that's not born in those gaps, it's born in the freedom of acceptance. The kind that does not have a listener, all it has is love. The kind that just IS.
For them in the prairies, their body, mind, and intellect work seamlessly to the rhythm of the wind. So much so there is no 'wind and them' --the 'wind is them'.
i hope i find that silence where I will lose i.