Anna's Hummer on vertical perch

The male Anna's Hummingbird that has chosen my yard as his own personal turf is having a harder and harder time defending it against other hummers, both Anna's and Rufous. Sometimes he even chooses to perch on the vertical wire just above the feeder, apparently hoping to prevent the others from even getting close to it. Unfortunately for him, he inevitably has to make a dash to defend the other feeder across the yard, and then the chase is on once again.