Ok I have no idea if this would work for an eagle but.... I have hawks in my backyard. I went to Harbor Freight and bought 2 of those windmill things that you are supposed to drive into the ground to chase away moles and voles. I mounted them on diagonal corners at the top of my chicken run and since they have been up not a single hawk has been back. All they do is spin in the wind like a windmill is supposed to but they flash as they do and they change direction to follow the wind. They look cool out there turning in the breeze, they dont affect my chickens at all and they dont seem to bother the local birds that I feed. maybe something like that scattered about your yard at different heights would deter the eagles?
best wishes
best wishes