I am amazed with the behavior of these little critters too!
I love to sit at my kitchen table and watch them coming and going, there is one little rascal who seems to play "King of the Mountain,"
He gets a drink and sits on the banister watching for any others and when one shows up he dives into them and chases the others away!
Here in MO the Red Throat-ed is the predominate species, and will be around here till about mid Sept.