We have been having some issues with our hummingbirds.  One of them has decided the feeder is his and no other birds can use it.  He sits around and feeds to his heart’s content.  Even when he is in a local tree, anyone coming close gets chased off quickly.  We have named him “Cartman”.  One of the recommendations in such a situation is to have a second feeder so we have added one to the fence nearby.  One of the benefits I have found with this is that it puts the birds at a different angle between me and the light and it brings out the colors more vibrantly.  Here you can see Cartman – he is still trying to dominate the place.