The cache is placed in the woods underneath a roosting place for a flock of vultures. My family and I were unaware of their, now apparent, residenece until I broke a large limb and sent them out of the trees with haste.
Like Grim Reapers, the vultures sit in absolute silence. Lacking a syrinx, or voice box, they cannot sing. If close enough, you might overhear an occasional hiss or groan as they communicate with one another, but they will usually not allow you that close.