Further to Hugo's note, isn't it also true that the
non-threatened species that often flock to bird feeders (and, as Hugo has also
pointed out, have actually benefited from Europeans' modifications to habitat -
Rainbow Lorikeets, Silver Gulls and Magpies included) are bullies which drive
out smaller and more timid birds, especially as they increase in local abundance
partially as a result of additional/artificial food sources? John, may I ask
what species are you attracting to your garden?