Is it barking at you? If so, approach it slowly, speaking gently, and toss it something nice to eat. (I use a few pellets of dry cat food.) A normal dog will soon learn that you are a friend and will not bark at you.

This is my standard procedure. I have no intention of putting up with an aggressive dog right on my home territory.

The people next door have a dachshund, and that is the only dog for which this plan has not worked. I'm convinced it has no intelligence whatever.

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As for the harrier, birds of prey like that can vary in color, one from another. The one you saw doesn't need to look just like the bird book. Also, their colors are more vivid during breeding season, which is probably over by now.