Proverbs/superstitions.

[Rankin, Robert L]

NPR's Morning Edition this a.m. (Thurs) carried a piece from a Hopi writer
in Flagstaff about story-telling in the Winter month(s). He mentioned that
they believe that in the coldest (lunar) month of Winter, spirits are
wandering about after dark so they don't whistle, make loud noises or beat
drums.

There's the belief about whistling attracting spirits again, this time from
the SW.  It seems to be widespread enough.

If you're in the MST or CST zones, you still may be able to hear it.

Bob