OH ok, I got it now !
But, I'm going to disagree with you on a point, and probably get myself broiled for it
My two are pretty brave, and very territorial. They would aggressively charge a strange being who violated that area, and... I'd encourage them to do just that.
That bird is not stupid, and you may be evaluating it's "hesitation" to flee because it's very aware of it's capabilities, and not going to expend the energy for flight, unless it sees the need for it. All animals have a preception of a "Life Distance", and apparently that distance was not encroached upon, or it would have fled immidately.
I'm thinking that a couple charges from your dogs (even a 7 pounder)toward the Bird, is going to make it very aware it's not welcome there.
Get your bigger Dog involved !
