O.K. 14:26 Today. I go and pick up my mail from the local boxes. I see a bird fighting the NW wind and finally land on a 40' fir tree. Just as I am opening my car door what do I hear but "THAT" call. I grab my binocs from the car and spot a Peregrine youngster perched about 20 yards away swaying in that tall fir tree and calling out. I can def. see the tan chest feathers and as it turns it's head I see the black eye-patch. But the call was what first alerted me. I kept my glasses on it for about 15 minutes.
Hadn't read this information before I answered on your new thread Willmax, but from your description, you saw a merlin, not a peregrine. Merlins have the malar stripe and young merlins and many adult merlins look just like juvenile peregrines. They also sound just like peregrines, as well as fly, hunt, etc, etc, etc. But its the tree that gives it away though, merlins nest in crow's nests in tall evergreens - they are woodland specialists and what you described is how you see 80% of merlins at this time of the year. Peregrines are big and sitting in evergreens is difficult when you aren't built to fly through branches ... yes, I know that sounds weird, but they hunt above trees (and buildings) and over waterbodies and open fields, they don't as a general rule hunt among trees - just too dangerous at the speeds they fly.
Here's a link to check the vocalizations you heard ....
http://www.allaboutbirds.org/guide/Merlin/soundsThese images don't show the malar stripe but they do show plumage in detail ...
As for the tall towers/grain elevators nearby, that doesn't increase the likelihood of it being a peregrine I'm afraid - peregrines aren't attracted to tall structures, they are attracted to tall structures near other tall structures on the banks of rivers/wetlands/lakes/oceans - not a few miles away from water, right on the water.