Yes, they do. I'm never confident that I won't be spotted until I get to over 25 feet. Seems almost like an invisible barrier to them above that point. I try to get 30 if I can and I don't recall ever being spotted up there. Tough to get that high in a lot of trees though.
In case anyone wonders, yes, that a measured height. I have a 25ft gear rope so I know where 25ft is.
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Still happily answering to the call-sign Peetza.

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You do not HAVE a soul. You ARE a soul. You HAVE a body.
-C.S. Lewis
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.